1
|
Broadbear JH, Depoortere RY, Vacy K, Ralph D, Tunstall BJ, Newman-Tancredi A. Discriminative stimulus properties of the 5-HT1A receptor biased agonists NLX-101 and F13714, in rats trained to discriminate 8-OH-DPAT from saline. Behav Pharmacol 2021; 32:652-659. [PMID: 34751175 PMCID: PMC8589115 DOI: 10.1097/fbp.0000000000000659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
NLX-101 and F13714 are selective, full efficacy, biased agonists of the serotonin (5-HT1A) receptor. NLX-101 preferentially activates cortical postsynaptic 5-HT1A receptors, whereas F13714 preferentially activates raphe nuclei presynaptic 5-HT1A receptors. We compared NLX-101 and F13714 for their efficacy and potency to substitute for the discriminative cue produced by the prototypical, nonbiased 5-HT1A receptor agonist 8-OH-DPAT (racemate). Male and female Sprague-Dawley rats were trained to discriminate 8-OH-DPAT (0.1 mg/kg i.p., 20 min pretreatment) from saline using a classical two-lever drug-discrimination procedure. 8-OH-DPAT (0.01 and 0.05 mg/kg i.p.) dose-dependently substituted for the training dose, with about 50% responding on the 8-OH-DPAT-associated lever at 0.05 mg/kg. F13714 fully and very potently substituted for the training dose of 8-OH-DPAT from 0.018 mg/kg i.p., whereas NLX-101 only achieved full substitution at 0.5 mg/kg i.p., a dose which is known to also activate presynaptic 5-HT1A receptors. The 5-HT1A receptor partial agonist, buspirone, partially substituted (~80%) at 1 and 2 mg/kg i.p., doses which also decreased response rates. F13714 decreased response rates at 0.05 mg/kg. The selective 5-HT1A receptor antagonist WAY-100 635 (1 mg/kg s.c., 40 min pretreatment) elicited almost no responding on the 8-OH-DPAT-associated lever by itself, but blocked the discriminative stimulus effects produced by administration (20 min pretreatment) of 8-OH-DPAT (0.1 mg/kg), F13714 (0.025 mg/kg), NLX-101 (0.5 mg/kg) or buspirone (1 mg/kg). These data suggest that the discriminative cue produced by 0.1 mg/kg i.p. 8-OH-DPAT results from activation of presynaptic 5-HT1A receptors. They also further demonstrate the distinct profiles in behavioral models of 5-HT1A receptor-biased agonists.
Collapse
Affiliation(s)
- Jillian H Broadbear
- Spectrum Personality Disorder Service, Richmond, Victoria, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | | | - Kristina Vacy
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
- The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - David Ralph
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Brendan J Tunstall
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
- Department of Pharmacology, Addiction Science, and Toxicology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | | |
Collapse
|
2
|
Guo J, Yan B, Wang F, Gao QH, Zhang XJ, Yu GJ, Zeng Y, Qiu JF, Geng Q, Han Q. [Establishment of a rat model of premature ejaculation with 8-OH-DPAT]. Zhonghua Nan Ke Xue 2018; 24:104-108. [PMID: 30156067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To explore the feasibility and practicability of establishing a rat model of premature ejaculation (PE) by injection of 8-OH-DPAT into the subarachnoid space of the lumbosacral spinal cord segments. METHODS Twenty-four male Wistar rats were equally randomized into a PE model and a blank control group. The PE model was established by injection of 8-OH-DPAT in 10 ml normal saline at 0.8 mg per kg of the body weight per day into the subarachnoid space of the lumbosacral spinal cord segments and the control rats were injected with the same volume of normal saline only, both for 4 weeks. Another 24 female Wistar rats were injected subcutaneously with benzoic acid estradiol at 20 μg to induce estrus at 36 hours before mated with the male animals. At 2 and 4 weeks, the male rats were mated with the female ones for 30 minutes each time and meanwhile observed for their mating behavior indicators, such as mount latency, intromission latency, ejaculation latency, mount frequency, intromission frequency, and ejaculation frequency. RESULTS Compared with the controls, the PE model rats showed a significantly lower ejaculation latency ([712.35 ± 36.77] vs [502.35 ± 46.72] s, P<0.05), mount latency ([11.22 ± 3.60] vs [8.69 ± 2.48] s, P<0.05), mount frequency (13.28 ± 0.24 vs 7.53 ± 1.84, P<0.05), and intromission latency ([22.33 ± 2.45] vs [12.08 ± 1.39] s, P<0.05), but a remarkably higher ejaculation frequency (2.01 ± 0.48 vs 4.26 ± 0.89, P<0.05). No statistically significant difference was observed between the control and model animals in the intromission frequency (7.49 ± 2.21 vs 6.45 ± 1.89, P>0.05). CONCLUSIONS A rat model of premature ejaculation was successfully established by injection of 8-OH-DPAT into the subarachnoid space of the lumbosacral spinal cord segments, which is of great significance for further study of the mechanism of premature ejaculation.
Collapse
Affiliation(s)
- Jun Guo
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Bin Yan
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Fu Wang
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Qing-He Gao
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Xiu-Ju Zhang
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Guo-Jin Yu
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Yin Zeng
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Jun-Feng Qiu
- Department of Andrology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Qiang Geng
- Department of Andrology, The First Affiliated Hospital of Tianjin University of Chinese Medicine, Tianjin 300192, China
| | - Qiang Han
- Department of Andrology, Beijing Traditional Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China
| |
Collapse
|
3
|
Lucot JB. Effects of naloxone on motion sickness in cats alone and with broad spectrum antiemetics. Auton Neurosci 2016; 202:97-101. [PMID: 27615675 DOI: 10.1016/j.autneu.2016.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/25/2016] [Accepted: 08/29/2016] [Indexed: 11/18/2022]
Abstract
Doses of naloxone far below those which elicit emesis increase the sensitivity to motion sickness. In order to evaluate the possible interaction with broad spectrum antiemetics, low doses of naloxone were tested alone and in combination with 8-hydroxy-2-(di-n-propylamine)tetralin (DPAT), fentanyl and the NK1 antagonist CP-99994. A modified autonomic symptom rating scale was unaffected by any drug and thus considered of little value. Fentanyl and NK1 antagonists decreased the duration of the retch/vomit sequence. Naloxone alone and in combination with each of the drugs increased the duration of retching/vomiting. Naloxone also increased the number of vomiting sequences. The results are interpreted in terms of possible site(s) of action of the antiemetic drugs.
Collapse
Affiliation(s)
- James B Lucot
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States.
| |
Collapse
|
4
|
Bonchak JG, Eby JM, Willenborg KA, Chrobak D, Henning SW, Krzywiec A, Johnson SL, Le Poole IC. Targeting melanocyte and melanoma stem cells by 8-hydroxy-2-dipropylaminotetralin. Arch Biochem Biophys 2014; 563:71-8. [PMID: 25132642 PMCID: PMC4221435 DOI: 10.1016/j.abb.2014.07.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/26/2014] [Accepted: 07/29/2014] [Indexed: 01/26/2023]
Abstract
Monobenzyl ether of hydroquinone (MBEH) is cytotoxic towards melanocytes. Its treatment efficacy is limited by an inability to eradicate stem cells. By contrast, 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-DPAT) affects melanocyte stem cell survival. MBEH and 8-DPAT were added to melanocytes and melanoma cells to compare cytotoxicity. Stem cell content among viable cells was determined by fluorocytometry using markers CD34, Pax3, and CD271. Immunostaining was used to identify stem cells in skin explants treated with MBEH or 8-DPAT ex vivo. Mice were exposed to MBEH or 8-DPAT and scanned for depigmentation before harvesting skin. MBEH exposure prompted a relative increase in stem cells among cultured melanocytes and melanoma cells, as treatment preferentially eliminated differentiated cells and spared the stem cells. Viability of this remaining, enriched stem cell population was however rapidly reduced by exposure to 8-DPAT within melanocyte and melanoma cell cultures. In human skin explants, the abundance of melanocyte stem cells was also visibly reduced after 8-DPAT treatment, in contrast to tissue exposed to MBEH. Meanwhile, significant depigmentation of the mouse pelage and loss of differentiated melanocytes was observed in vivo in response to topical application of MBEH, but not 8-DPAT. Prolonged application of the latter agent instead appeared to effectively reduce the abundance of melanocyte stem cells in the dermis. This furthers the idea that MBEH and 8-DPAT target complementary cell populations. Results indicate that combination treatment may demonstrate superior therapeutic activity by eliminating both differentiated and tumor initiating populations.
Collapse
Affiliation(s)
- Jonathan G Bonchak
- Departments of Medicine and Radiology, Loyola University Medical Center, Maywood, IL, USA
| | - Jonathan M Eby
- Oncology Research Institute, Loyola University Medical Center, Maywood, IL, USA
| | | | - David Chrobak
- Oncology Research Institute, Loyola University Medical Center, Maywood, IL, USA
| | - Steven W Henning
- Oncology Research Institute, Loyola University Medical Center, Maywood, IL, USA
| | - Anna Krzywiec
- Illinois Mathematics and Science Academy, Aurora, IL, USA
| | - Steven L Johnson
- Department of Genetics, Washington University School of Medicine, St. Louis, MA, USA
| | - I Caroline Le Poole
- Oncology Research Institute, Loyola University Medical Center, Maywood, IL, USA; Departments of Pathology, Microbiology and Immunology, Loyola University Medical Center, Maywood, IL, USA.
| |
Collapse
|
5
|
Kozhevnikova LM, Moskovtsev AA, Mesitov MV. [The Effects of Inhibitors of Rho- and tyrosine c-Src-kinases on serotonin-induced constrictions of the aorta and mesenteric artery in rats]. Izv Akad Nauk Ser Biol 2014:500-509. [PMID: 25720289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We found that the inhibitor of Rho-kinase fasudil selectively inhibited constriction of isolated rings of the aorta and mesenteric artery in rats in response to application of the agonists of 5HT2A-(DOI and TBC-2) and 5HT1A-receptors (8-OH-DPAT) and did not influence vasoconstriction induced by serotonin. We demonstrate for the first time that application of the agonists of 5HT2C-receptors (MK 212 and SCH 23390) did not influence the tone of "intact" vessels. The marked vasoconstrictory effect of the agonists of 5HT2C-receptors was observed in the vessels preconstricted due to angiotensin II or vasopressin. We found that the inhibitor of Rho-kinase did not influence negatively on MK 212 or SCH 23390-induced constriction of isolated rings of the aorta and mesenteric artery in rats. We suppose.that, in the presence of fasudil, serotonin induces constriction of vessels through the interaction with 5HT2C-receptors and signal transduction from these receptors does not involve Rho-kinase activity. We found that fasudil attenuated vasoconstriction induced by norepinephrine and vasopressin by 40%. We.demonstrated that tyrosine c-Src-kinase plays the most important role in signal transduction from 5HT-receptors because its effects are specific with relation to these receptors.
Collapse
|
6
|
Gerasimova IA, Sidorina AA, Kuleshova EA, Merzhanova GH. [Behavioral effects during the local activation and blockade of serotonin and dopamine receptors in the frontal cortex in cats in the model with a choice of reinforcements of different value]. Zh Vyssh Nerv Deiat Im I P Pavlova 2013; 63:699-710. [PMID: 25464760 DOI: 10.7868/s0044467713060051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the model with a choice of reinforcements of different value animals were able to "impulsive" and "self-controlled" behavior with an equal probability. Five adult cats were tested. A local application of agonists of 5-HT(1A) and 5-HT(2A/C) receptors (8-OH-DPAT, DOI) in the frontal cortex have resulted in a significant decrease of the "impulsive" reactions and an increase of omissions. The administration of antagonists of 5-HT(2A/C) receptors (ketanserin) and D1/D2 receptors (SCH 23390, raclopride) have impaired the "impulsive" behavior. However the combined administration of agonists/antagonists of 5-HT(2A/C) receptors and antagonists of D1/D2 receptors have not shown the significant changes in behavior as compared with control experiments. The data showed the realization of the optimal behavior with the "impulsive" and "self-controled" reactions in ambivalent animals requires the involvement of both dopaminergic and serotoninergic systems for the regulation of the activity of neurons in frontal cortex areas.
Collapse
|
7
|
Nakatani Y, Suzuki M, Tokunaga M, Maeda J, Sakai M, Ishihara H, Yoshinaga T, Takenaka O, Zhang MR, Suhara T, Higuchi M. A small-animal pharmacokinetic/pharmacodynamic PET study of central serotonin 1A receptor occupancy by a potential therapeutic agent for overactive bladder. PLoS One 2013; 8:e75040. [PMID: 24086433 PMCID: PMC3781034 DOI: 10.1371/journal.pone.0075040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/08/2013] [Indexed: 02/06/2023] Open
Abstract
Serotonin 1A (5-HT1A) receptors have been mechanistically implicated in micturition control, and there has been a need for an appropriate biomarker surrogating the potency of a provisional drug acting on this receptor system for developing a new therapeutic approach to overactive bladder (OAB). Here, we analyzed the occupancy of 5-HT1A receptors in living Sprague-Dawley rat brains by a novel candidate drug for OAB, E2110, using positron emission tomography (PET) imaging, and assessed the utility of a receptor occupancy (RO) assay to establish a pharmacodynamic index translatable between animals and humans. The plasma concentrations inducing 50% RO (EC50) estimated by both direct and effect compartment models were in good agreement. Dose-dependent therapeutic effects of E2110 on dysregulated micturition in different rat models of pollakiuria were also consistently explained by achievement of 5-HT1A RO by E2110 in a certain range (≥ 60%). Plasma drug concentrations inducing this RO range and EC50 would accordingly be objective indices in comparing pharmacokinetics-RO relationships between rats and humans. These findings support the utility of PET RO and plasma pharmacokinetic assays with the aid of adequate mathematical models in determining the in vivo characteristics of a drug acting on 5-HT1A receptors and thereby counteracting OAB.
Collapse
Affiliation(s)
- Yosuke Nakatani
- Tsukuba Research Laboratories, Eisai Co, Ltd., Tsukuba, Ibaraki, Japan ; Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Chiba, Japan ; Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Wright MJ, Angrish D, Aarde SM, Barlow DJ, Buczynski MW, Creehan KM, Vandewater SA, Parsons LH, Houseknecht KL, Dickerson TJ, Taffe MA. Effect of ambient temperature on the thermoregulatory and locomotor stimulant effects of 4-methylmethcathinone in Wistar and Sprague-Dawley rats. PLoS One 2012; 7:e44652. [PMID: 22952999 PMCID: PMC3432134 DOI: 10.1371/journal.pone.0044652] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 08/06/2012] [Indexed: 11/24/2022] Open
Abstract
The drug 4-methylmethcathinone (4-MMC; aka, mephedrone, MMCAT, “plant food”, “bath salts”) is a recent addition to the list of popular recreational psychomotor-stimulant compounds. Relatively little information about this drug is available in the scientific literature, but popular media reports have driven recent drug control actions in the UK and several US States. Online user reports of subjective similarity to 3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”) prompted the current investigation of the thermoregulatory and locomotor effects of 4-MMC. Male Wistar and Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1–10 mg/kg ) using an implantable radiotelemetry system under conditions of low (23°C) and high (27°C) ambient temperature. A reliable reduction of body temperature was produced by 4-MMC in Wistar rats at 23°C or 27°C with only minimal effect in Sprague-Dawley rats. Increased locomotor activity was observed after 4-MMC administration in both strains with significantly more activity produced in the Sprague-Dawley strain. The 10 mg/kg s.c. dose evoked greater increase in extracellular serotonin, compared with dopamine, in the nucleus accumbens. Follow-up studies confirmed that the degree of locomotor stimulation produced by 10 mg/kg 4-MMC was nearly identical to that produced by 1 mg/kg d-methamphetamine in each strain. Furthermore, hypothermia produced by the serotonin 1A/7 receptor agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) was similar in each strain. These results show that the cathinone analog 4-MMC exhibits thermoregulatory and locomotor properties that are distinct from those established for methamphetamine or MDMA in prior work, despite recent evidence of neuropharmacological similarity with MDMA.
Collapse
Affiliation(s)
- M. Jerry Wright
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Deepshikha Angrish
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, United States of America
| | - Shawn M. Aarde
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Deborah J. Barlow
- Department of Pharmaceutical Sciences, University of New England, Portland, Maine, United States of America
| | - Matthew W. Buczynski
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Kevin M. Creehan
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sophia A. Vandewater
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Loren H. Parsons
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Karen L. Houseknecht
- Department of Pharmaceutical Sciences, University of New England, Portland, Maine, United States of America
| | - Tobin J. Dickerson
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, United States of America
| | - Michael A. Taffe
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
| |
Collapse
|
9
|
Zaĭchenko MI, Merzhanova GK, Vanetsian GL. [Effect of the selective ligands 5-HT(1A) receptors administration on the impulsive and self-control behavior in rats]. Zh Vyssh Nerv Deiat Im I P Pavlova 2012; 62:465-474. [PMID: 23035563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of drugs, agonist and antagonist of serotonin receptors 5-HT(1A) on the behavior of rats tested by the method of choice to the value of reinforcement was investigated. Depending on their preferences in food reinforcement rats were divided into self-monitoring (choosing more valuable, delayed reinforcement) and impulsive (low value, immediate reinforcement). An hour before the test animals were administrated i.p. agonist 5-HT(1A) receptors 8-OH-DPAT, [(+)-8-Hydroxy-2-(dipropylamino)tetralin] in a dose of 0.1 mg/kg or antagonist WAY-100635, [N-[2-[4-(2-Methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide maleat salt] at a dose of 0.2 mg/kg. Evaluated parameters, such as number of clicks on a particular pedal, the latencies and number of omitted responses. The results showed that the administration of drugs to modify individual behavior parameters both groups of animals. The introduction of 5-HT(1A) agonist receptors in impulsive animals caused an increase in the number of clicks on the pedal for more valuable reinforcement, and administration of an antagonist did not have any significant effect to behavior.
Collapse
|
10
|
Al'perina EL, Zhukova EN, Iur'ev DV, Idova GV. [Effect of activation of serotonin 5-HT1A-receptors on the immune response in mice of the ASC strain with depressive-like behavior]. Zh Vyssh Nerv Deiat Im I P Pavlova 2012; 62:243-249. [PMID: 22690554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Selective activation of serotonin 5-HT(1A)-receptors produced different effects on immunological reactivity in mice of ASC strain with genetic predisposition to depressive-like behavior, and parental CBA and AKR strains displaying no depressive reactions. Administration of 5-HT(1A)-receptors agonist 8-OH-DPAT at low dose (0.1 mg/kg) affecting upon presynaptic receptors resulted in immunostimulation in CBA mice and did not change the immune response level in mice of ASC strain. Activation of postsynaptic 5-HT(1A)-receptors with higher dose of 8-OH-DPAT (1.0 mg/kg) caused immunosuppression in CBA and AKR strains while under the same conditions the immune response of ASC mice was increased. Decrease the immune reactions in ASC mice was observed only after application of 8-OHDPAT at dose of 5 mg/kg. The changes of functional activity of pre- and postsynaptic 5-HT(1A)-receptors under a high predisposition to depressive-like behavior providing different effects of this receptor activation on immune function are discussed.
Collapse
|
11
|
Haleem DJ, Samad N, Perveen T, Haider S, Haleem MA. ROLE OF SEROTONIN-1A RECEPTORS IN RESTRAINT-INDUCED BEHAVIORAL DEFICITS AND ADAPTATION TO REPEATED RESTRAINT STRESS IN RATS. Int J Neurosci 2009; 117:243-57. [PMID: 17365111 DOI: 10.1080/00207450500534084] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a selective 5-hydroxy-tryptamine (5-HT; serotonin)-1A agonist was used to evaluate the role 5-HT-1 A receptors in restraint-induced behavioral deficits and adaptation to repeated restraint stress in rats. Animals were injected with 8-OH-DPAT at a dose of 0.25 mg/kg 1 h before exposing to an episode of 2 h/day restraint stress daily for 5 days. Effects of drug administration and restraint stress on 24 h cumulative food intakes were monitored daily. Intensity of 8-OH-DPAT-induced serotonin syndrome was also monitored each day before submitting animals to the episode of stress. Exposure to the first episode of 2 h restraint stress resulted in a decrease in 24 h cumulative food intake and an attenuation of 8-OH-DPAT-induced serotonin syndrome monitored next day. The deficits attenuated following 2nd and 3rd 2 h/day restraint were not observed following the 4th and 5th 2 h/day restraint. The decreases of food intake following 1st and 2nd day restraint sessions were smaller in 8-OH-DPAT than saline-injected animals. Administration of 8-OH-DPAT on day 6 elicited comparable serotonin syndrome in unrestrained and repeatedly restrained groups. Brain 5-HT metabolism decreased in unrestrained but not repeatedly restrained animals. The results suggest that a decrease in serotonergic neurotransmission is involved in restraint-induced behavioral deficits while a normalization of serotonin neurotransmission due to desensitization of somatodendritic 5-HT-1A receptors may help cope with the stress demand to produce adaptation to stress.
Collapse
Affiliation(s)
- Darakhshan J Haleem
- Department of Biochemistry, Neurochemistry and Biochemical Neuropharmacology, Research Laboratory, University of Karachi, Karachi, Pakistan.
| | | | | | | | | |
Collapse
|
12
|
Perez-Garcia G, Meneses A. Memory time-course: mRNA 5-HT1A and 5-HT7 receptors. Behav Brain Res 2009; 202:102-13. [PMID: 19447286 DOI: 10.1016/j.bbr.2009.03.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/15/2009] [Accepted: 03/16/2009] [Indexed: 11/17/2022]
Abstract
In an attempt to clarify conflicting results about serotonin (5-hydroxytryptamine, 5-HT) 5-HT(1A) and 5-HT(7) receptors in memory formation, their mRNA expression was determined by RT-PCR in key brain areas for explicit and implicit memory. The time-course (0-120 h) of autoshaped responses was progressive and mRNA 5-HT(1A) or 5-HT(7) receptors expression monotonically augmented or declined in prefrontal cortex, hippocampus and raphe nuclei, respectively. At 24-48 h acutely 8-OH-DPAT (0.062 mg/kg) administration enhanced memory and attenuated mRNA 5-HT(1A)<5-HT(7) receptors expression respect to saline group. WAY100635 (0.3 mg/kg) or SB-269970 (10.0 mg/kg) did not affect the former, partially blocked or reversed the latter, respectively. Furthermore, lower WAY100635 (0.001-0.1 mg/kg) or SB-269970 (1.0-5.0 mg/kg) doses plus 8-OHDPAT not affected memory; however both combinations suppressed or up-regulated mRNA expression 5-HT(1A) or 5-HT(7) receptors. In contrast, AS19 (5.0 mg/kg) facilitated memory consolidation, decreased or increased hippocampal 5-HT(7) and 5-HT(1A) receptors expression. Together these data revealed that, when both 5-HT(1A) and 5-HT(7) receptors were stimulated by 8-OHDPAT under memory consolidation, subtle changes emerged, not evident at behavioral level though detectable at genes expression. Notably, high levels of efficient memory were maintained even when serotonergic tone, via either 5-HT(1A) or 5-HT(7) receptor, was down- or up-regulated. Nevertheless, WAY100635 plus SB-269970 impaired memory consolidation and suppressed their expression. Considering that serotonergic changes are prominent in AD patients with an earlier onset of disease the present approach might be useful in the identification of functional changes associated to memory formation, memory deficits and reversing or even preventing these deficits.
Collapse
|
13
|
Carey RJ, Damianopoulos EN, Shanahan AB. Cocaine conditioning: reversal by autoreceptor dose levels of 8-OHDPAT. Pharmacol Biochem Behav 2009; 91:447-52. [PMID: 18804487 PMCID: PMC2716395 DOI: 10.1016/j.pbb.2008.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 11/29/2022]
Abstract
In order to investigate the contribution of serotonergic effects of cocaine to Pavlovian conditioning of cocaine locomotor stimulant effects, two experiments were conducted in which groups of rats (N=10) received cocaine treatments (10 mg/kg) paired or unpaired to placement in an open-field environment. Initially, a cocaine conditioned locomotion stimulant effect was established. Next, additional Coc-P and Coc-UP pairings were carried out in conjunction with pretreatment injections of the 5-HT1A agonist, 8-OHDPAT (0.01, 0.025 and 0.05 mg/kg) or saline. In experiment 1, the Coc-P group which received the saline pretreatment again exhibited conditioning but in the 8-OHDPAT pretreatment Coc-P group conditioning was eliminated. In the second experiment, the protocol of the first experiment was repeated but expanded in the post-conditioning phase to include an 8-OHDPAT plus the 5-HT1A antagonist pretreatment Coc-P group. As in the first experiment, the 8-OHDPAT pretreatment Coc-P group did not exhibit a cocaine conditioned locomotion stimulant effect; whereas, the saline pretreatment Coc-P and the 8-OHDPAT plus WAY-100635 pretreatment Coc-P groups did exhibit the cocaine conditioned locomotion stimulant effect. These findings are consistent with an important role for serotonin in the maintenance of cocaine Pavlovian conditioned effects.
Collapse
Affiliation(s)
- Robert J Carey
- Research Service (151), VA Medical Center, 800 Irving Avenue, Syracuse, NY 13210, USA.
| | | | | |
Collapse
|
14
|
Besnard S, Massé F, Verdaguer M, Cappelin B, Meurice JC, Gestreau C. Time- and dose-related effects of three 5-HT receptor ligands on the genioglossus activity in anesthetized and conscious rats. Sleep Breath 2008; 11:275-84. [PMID: 17457631 DOI: 10.1007/s11325-007-0107-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Clinical trials in obstructive sleep apnea syndrome patients reported moderate effects of serotoninergic drugs on oropharyngeal apneas, although numerous specific 5-HT ligands highly modulate the genioglossus muscle (GG) activity in experiments performed in anesthetized animals. The purpose of this study was to investigate time- and dose-related effects of central and systemic injections of 8-OHDPAT (5-HT1A agonist), SB224289 (5-HT1B antagonist), and DOI (5-HT2A/2C agonist) on the GG activity in anesthetized and conscious rats. Electromyographic recordings of the GG activity (GGemg) were analyzed after central and systemic injections of each drug in ketamine-xylazine anesthetized rats. Electroencephalograms (EEG), as well as neck and GG muscle activities (Nemg and GGemg), were recorded in 15 additional rats to analyze changes in sleep-wake states before and after systemic injection of the drugs. Central injections of 8-OHDPAT and DOI in anesthetized rats induced clear dose-related increases in phasic and tonic GGemg activities, respectively. The time-responses were inferior to 30 min with 8-OHDPAT and over 50 min with DOI. Moderate increases in phasic GGemg activity were also observed after central, but not peripheral injection of SB and DOI. The total sleep time measured in conscious rats significantly decreased after systemic injections of DOI and 8-OHDPAT, although no change was observed in phasic or tonic GGemg activity. The dose- and time-responses of the DOI in anesthetized rat partly explain the lack of GGemg tonic change in conscious rat. The moderate effect on the GGemg phasic activity of peripheral 5-HT1A ligand injection easily explains the lack of change in conscious rat. The serotonergic modulation of the respiratory component of the GGemg remains complex, but is highly sensitive to 5-HT1A receptors after central injection in rats under anesthesia. Forthcoming therapy in OSAS should be made of mixed profiled neurotransmitters and different routes of administration.
Collapse
Affiliation(s)
- S Besnard
- Neurophysiologie Clinique-Sommeil CHU de Poitiers, Université de Poitiers, 2 rue de la Milétrie, 86021 Poitiers cedex, France.
| | | | | | | | | | | |
Collapse
|
15
|
Valic M, Pecotic R, Dogas Z. Phrenic nerve activity is enhanced by 5-HT1A receptor agonist 8-OH-DPAT in spontaneously breathing anesthetized rats. J Physiol Pharmacol 2008; 59:17-25. [PMID: 18441384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 01/22/2008] [Indexed: 05/26/2023]
Abstract
Activation of serotonin 1A (5-HT(1A)) receptors has been shown to have diverse effects on respiration. The purpose of this study was to determine changes in respiratory motor pattern of phrenic nerve activity and respiratory rhythm after systemic application of specific 5-HT(1A) receptor agonist 8-hydroxy-2-di-npropylamino-tetralin (8-OH-DPAT). We hypothesized that systemic application of specific 5-HT(1A) receptor agonist 8-OH-DPAT in spontaneously breathing anaesthetized rats will enhance phrenic motor output and phrenic respiratory rate. The study was performed in spontaneously breathing urethane anesthetized rats. Intravenous application of 8-OH-DPAT produced dose dependent increase in the amplitude of integrated phrenic nerve activity and disturbances in respiratory rhythm. Stimulating effect of 8-OH-DPAT on phrenic nerve activity was abolished by intravenous application of the selective 5-HT(1A) receptor antagonist WAY, N-(2-(4,2-methoxyphenyl)-1-piperazinyl)ethyl)-N-2-pyridinyl-cyclohexane-carboxamide maleate (WAY-100635). These results show that stimulation of 5-HT(1A) receptors by intravenous application of 8-OH-DPAT enhances phrenic nerve activity in spontaneously breathing rats.
Collapse
Affiliation(s)
- M Valic
- Department of Neuroscience, University of Split School of Medicine, Split, Croatia
| | | | | |
Collapse
|
16
|
Abstract
The modulation of learning and memory after left or right microinjections of the selective 5-HT1A receptor agonist 8-OH-DPAT and of the 5-HT1A receptor antagonist NAN190 into the hippocampal CA1 area of male Wistar rats was studied. Microinjections of 8-OH-DPAT (1 microg) into the right or left CA1 hippocampal area produced a significant decrease in the number of avoidances in a shuttle box. The impairing effect of 8-OH-DPAT was more pronounced when injected into the right hippocampus compared to the left one. Microinjections of NAN190 (1 microg) into the right or left CA1 hippocampal area produced a significant increase in the number of avoidances in a shuttle box. Right microinjections of NAN190 increased the number of avoidances more strongly than compared to left injections. These effects on learning and memory were more pronounced after injection of either of the serotonergic agents into the right CA1 hippocampal area compared to the left. The stronger memory-modulating effect after injection of 8-OH-DPAT or NAN190 into the right CA1 hippocampal area suggests a rightward bias in the rat.
Collapse
Affiliation(s)
- I Belcheva
- Bulgarian Academy of Sciences, Sofia, Bulgaria.
| | | | | |
Collapse
|
17
|
Lu MC, Hsieh MT, Wu CR, Cheng HY, Hsieh CC, Lin YT, Peng WH. Ameliorating effect of emodin, a constitute of Polygonatum multiflorum, on cycloheximide-induced impairment of memory consolidation in rats. J Ethnopharmacol 2007; 112:552-6. [PMID: 17572029 DOI: 10.1016/j.jep.2007.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 03/23/2007] [Accepted: 05/01/2007] [Indexed: 05/15/2023]
Abstract
The aim of the present study was intended to investigate the ameliorating effects of emodin on memory consolidation via cholinergic, serotonergic and GABAergic neuronal systems in rats. First, we evaluated the ameliorating effects of emodin on cycloheximide (CXM)-induced impairment of passive avoidance response in rats. Secondly, we clarified the role of cholinergic, serotonergic or GABAergic system on the ameliorating effect of emodin by using 5-HT1A receptor partial agonist, 5-HT2 receptor antagonist, GABAB agonist, GABAA antagonist and muscarinic receptor antagonist. Emodin protected the rat from CXM-induced memory consolidation impairment. The beneficial effect of emodin on CXM-induced memory consolidation impairment was amplified by 8-OH-DPAT (5-HT1A receptor partial agonist) and ritanserin (5-HT2 receptor antagonist), but reduced by scopolamine. These results suggested that the beneficial effect of emodin on CXM-induced memory consolidation impairment was amplified by serotonergic 5-HT1A-receptor partial agonist and 5-HT2 receptor antagonist but reduced by muscarinic receptor antagonist.
Collapse
Affiliation(s)
- Ming-Chin Lu
- Post-Baccalaureate School of Chinese Medicine, China Medical University, Taichung, Taiwan, ROC
| | | | | | | | | | | | | |
Collapse
|
18
|
Curran AK, Leiter JC. Baroreceptor-mediated inhibition of respiration after peripheral and central administration of a 5-HT1Areceptor agonist in neonatal piglets. Exp Physiol 2007; 92:757-67. [PMID: 17392335 DOI: 10.1113/expphysiol.2007.037481] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Inhibition of neurones in the ventral medulla accentuates the respiratory inhibition associated with acute blood pressure elevation in piglets. Activation of presynaptic 5-HT(1A) receptors inhibits serotonergic neurones in the ventral medulla and caudal raphé, and we tested the hypothesis that administration of 8-hydroxydipropylaminotetralin (8-OH-DPAT), a 5-HT(1A) agonist, within the rostroventral medulla and caudal raphé would enhance baroreceptor-mediated inhibition of respiratory activity in decerebrate, neonatal piglets. Baroreceptor stimulation was achieved by inflating a balloon in the distal aorta to elevate carotid blood pressure. After two to four control trials of baroreceptor stimulation, each piglet was given either a single intravenous (i.v.) dose of 10 microg kg(-1) 8-OH-DPAT or treated by adding 10 or 30 mm 8-OH-DPAT to the dialysate for approximately 10 min to inhibit serotonergic neurones, after which the baroreceptor stimulation trials were repeated. Baroreceptor stimulation reduced respiratory activity, particularly the respiratory frequency, which diminished from 35.7 +/- 3.3 to 33.8 +/- 3.1 breaths min(-1) (P < 0.02) and, following i.v. 8-OH-DPAT, baroreceptor-mediated inhibition of respiratory output was significantly accentuated (P < 0.05); the respiratory frequency declined from 34.5 +/- 3.6 to 26.5 +/- 2.9 breaths min(-1). Increasing aortic blood pressure reduced the respiratory frequency (P < 0.01), but focal dialysis of 10 or 30 mm 8-OH-DPAT had, on average, no effect on the ventilatory inhibition associated with an acute elevation of blood pressure. We conclude that activation of 5-HT(1A) receptors after systemic administration of 8-OH-DPAT enhanced baroreflex-mediated inhibition of ventilation, but this effect cannot be attributed to 5-HT(1A) receptor activation within the rostroventral medulla and caudal raphé.
Collapse
Affiliation(s)
- Aidan K Curran
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756, USA
| | | |
Collapse
|
19
|
Cheng JP, Aslam HA, Hoffman AN, Zafonte RD, Kline AE. The neurobehavioral benefit conferred by a single systemic administration of 8-OH-DPAT after brain trauma is confined to a narrow therapeutic window. Neurosci Lett 2007; 416:165-8. [PMID: 17321680 PMCID: PMC1876743 DOI: 10.1016/j.neulet.2007.02.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 02/01/2007] [Accepted: 02/01/2007] [Indexed: 11/15/2022]
Abstract
The 5-HT(1A) receptor agonist 8-OH-DPAT (0.5mg/kg) enhances behavioral recovery when administered 15min after experimental traumatic brain injury (TBI). To determine if benefits are still attainable at clinically relevant times, treatment was delayed 1 and 2h post-TBI and motor/cognitive performance was compared to early (i.e., 15min) administration. No differences were observed among the vehicle and 8-OH-DPAT groups treated at 1 and 2h, but all three were significantly impaired versus early 8-OH-DPAT. The data suggest that an early and narrow critical period exists for the behavioral recovery afforded by a single 8-OH-DPAT treatment paradigm. The critical window corresponds to the well documented TBI-induced glutamate increase, suggesting that 8-OH-DPAT may be conferring neuroprotection by attenuating this acute deleterious surge.
Collapse
Affiliation(s)
- Jeffrey P Cheng
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | | | | | | |
Collapse
|
20
|
Ebenezer IS, Surujbally A. The effects of 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) on food intake in non-deprived C57BL6 mice. Eur J Pharmacol 2007; 559:184-8. [PMID: 17300778 DOI: 10.1016/j.ejphar.2007.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 12/27/2006] [Accepted: 01/08/2007] [Indexed: 10/23/2022]
Abstract
The effects of the 5HT1A agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) were investigated on food intake in non-deprived mice. 8-OH-DPAT (50-200 mg/kg) administered subcutaneously (s.c.) 5 min prior to presentation of food, produced a dose-related increase in cumulative food intake in C57BC6 mice. The hyperphagic effect of 8-OH-DPAT (100 mg/kg, s.c.) was abolished by concurrent treatment with the 5HT1A receptor antagonist N-[2-(4-2-methoxyphenyl)-1-piperazinyl]-N-(2-pyridyl) cyclohexanecarboxamide (WAY100635; 0.3 mg/kg, s.c.). These data show that 8-OH-DPAT produces an increase in food consumption in non-deprived mice by a 5-HT1A receptor-mediated mechanism of action.
Collapse
Affiliation(s)
- Ivor S Ebenezer
- Neuropharmacology Research Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK.
| | | |
Collapse
|
21
|
Selvamani A, Lincoln C, Uphouse L. The PKC inhibitor, bisindolymaleimide, blocks DOI's attenuation of the effects of 8-OH-DPAT on female rat lordosis behavior. Behav Brain Res 2007; 179:99-106. [PMID: 17336403 PMCID: PMC1950743 DOI: 10.1016/j.bbr.2007.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2006] [Revised: 01/05/2007] [Accepted: 01/23/2007] [Indexed: 12/12/2022]
Abstract
Ovariectomized rats with bilateral cannulae near the ventromedial nucleus of the hypothalamus were hormonally primed with 10 microg estradiol benzoate and 500 microg progesterone. Sexually receptive females were infused bilaterally with 200 ng of the 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), or with a combination of 200 ng 8-OH-DPAT and 2000 ng of the 5-HT(2) receptor agonist, (+/-)-2,5-dimethoxy-4-iodophenyl-2-aminopropane HCl (DOI). 8-OH-DPAT inhibited lordosis behavior and DOI reduced this inhibition. However, if females were preinfused with the PKC inhibitor, bisindolymaleimide I hydrochloride (BIM), DOI's effect was eliminated. BIM's attenuation of the effects of DOI was time-dependent. When BIM was infused 90 min, but not 30 min, before the 5-HT receptor agonists, BIM eliminated DOI's protection against the lordosis-inhibiting effects of 8-OH-DPAT. A concentration of BIM as low as 10(-5) nmol in a 0.5 microl infusion volume was effective and there was little evidence of dose responsivity between 10(-5) and 10(-1) nmol of BIM. In contrast, prior infusion with vehicle or with 10(-7) nmol BIM had no impact on the female's response to the 5-HT receptor agonists. These findings allow the suggestion that DOI's ability to increase PKC may be responsible for attenuation of the effects of 8-OH-DPAT on lordosis behavior.
Collapse
Affiliation(s)
- Amutha Selvamani
- Department of Biology, Texas Woman's University, Denton, TX 76204, USA
| | | | | |
Collapse
|
22
|
Dabrowska J, Nowak P, Brus R. Desensitization of 5-HT(1A) autoreceptors induced by neonatal DSP-4 treatment. Eur Neuropsychopharmacol 2007; 17:129-37. [PMID: 16679005 DOI: 10.1016/j.euroneuro.2006.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 02/07/2006] [Accepted: 03/21/2006] [Indexed: 11/19/2022]
Abstract
To examine the effect of noradrenergic lesion on the reactivity of central 5-HT(1A) receptors, DSP-4 (50 mg/kg) was administered neonatally 30 min after zimelidine (10 mg/kg) administration. 5-HT(1A) autoreceptors are involved in the regulation of serotonin (5-HT) synthesis. In HPLC assay R-(+)-8-OH-DPAT (0.03 mg/kg) significantly decreased 5-HT synthesis rate in striatum, hypothalamus and frontal cortex of control, whilst nonsignificantly in DSP-4-lesioned adult rats (10-12 weeks old). To determine which type of receptor, pre- or postsynaptically located, is involved in the attenuated response to 5-HT(1A) receptors' agonist, behavioral tests were conducted. R-(+)-8-OH-DPAT (0.015 mg/kg) caused hyperphagia of control rats, but did not change feeding of DSP-4 treated rats. R-(+)-8-OH-DPAT (0.1 mg/kg) induced hypothermia and "5-HT(1A) syndrome" in both control and DSP-4-lesioned animals. The nature of this phenomenon is attributable to the presynaptic adaptive mechanism and suggests the desensitization of 5-HT(1A) autoreceptors of rats with neonatal lesion of the central noradrenergic system.
Collapse
Affiliation(s)
- Joanna Dabrowska
- Department of Pharmacology, Medical University of Silesia, 38 Jordana St., 41-808 Zabrze, Poland.
| | | | | |
Collapse
|
23
|
Ebenezer IS, Arkle MJ, Tite RM. 8-Hydroxy-2-(di-N-propylamino)-tetralin (8-OH-DPAT) inhibits food intake in fasted rats by an action at 5-HT1A receptors. ACTA ACUST UNITED AC 2007; 29:269-72. [PMID: 17609739 DOI: 10.1358/mf.2007.29.4.1075362] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The effects of the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) on food intake were investigated in food-deprived rats. 8-OH-DPAT (25-100 microg/kg) administered subcutaneously immediately prior to the presentation of food produced a dose-related decrease in food intake in rats that had been fasted for 22 h. The hypophagic effect of 8-OH-DPAT (50 microg/kg) was abolished by pretreatment with the selective 5-HT1A receptor antagonist n-[2-(4-2-methoxyphenyl)-1-piperazinyl]-n-(2-pyridyl) cyclohexanecarboxamide (WAY 10063; 0.3 mg/kg). The results of this study show that the acute dose-dependent depressant effect of 8-OH-DPAT on food intake in fasted rats is mediated by an action at 5-HT1A receptors.
Collapse
Affiliation(s)
- I S Ebenezer
- Neuropharmacology Research Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, Hampshire, England, UK.
| | | | | |
Collapse
|
24
|
Carrasco GA, Van de Kar LD, Jia C, Xu H, Chen Z, Chadda R, Garcia F, Muma NA, Battaglia G. Single Exposure to a Serotonin 1A Receptor Agonist, (+)8-Hydroxy-2-(di-n-propylamino)-tetralin, Produces a Prolonged Heterologous Desensitization of Serotonin 2A Receptors in Neuroendocrine Neurons in Vivo. J Pharmacol Exp Ther 2006; 320:1078-86. [PMID: 17159160 DOI: 10.1124/jpet.106.116004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously demonstrated colocalization of serotonin 1A (5-HT(1A)) and serotonin 2A (5-HT(2A)) receptors in oxytocin and corticotropin-releasing factor neurons in the hypothalamic paraventricular nucleus (PVN). Because a functional imbalance between hypothalamic 5-HT(1A) and 5-HT(2A) receptors has been implicated in several neuropsychiatric disorders, in this study we investigated whether acute in vivo activation of 5-HT(1A) receptors in the PVN results in desensitization of 5-HT(2A) receptor signaling. Functional desensitization of hypothalamic 5-HT(2A) receptors was assessed via a reduction in oxytocin and adrenocorticotropin (ACTH) responses to the 5-HT(2A/2C) receptor agonist (-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl [(-)DOI]. We report here that a single systemic injection of the 5-HT(1A) receptor agonist (+)-8-hydroxy-2-(di-n-propylamino)-tetralin [(+)8-OH-DPAT] (200 microg/kg) significantly reduced the 5-HT(2A) receptor-mediated oxytocin responses for at least 72 h. Direct intraparaventricular injection of (+)8-OH-DPAT (0.2 nmol) 24 h before a submaximal dose of (-)DOI (0.35 mg/kg) significantly inhibited the 5-HT(2A) receptor-mediated increases in both oxytocin and ACTH (-39 and -16%, respectively). In addition, the (+)8-OH-DPAT-induced desensitization of the 5-HT(2A) receptor-mediated oxytocin but not the ACTH response was inhibited in rats pretreated with either a systemic (0.1 mg/kg) or intraparaventricular (10 nmol) injection of the 5-HT(1A) receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY100635). This is the first in vivo demonstration of a prolonged heterologous intracellular desensitization of 5-HT(2A) receptors after acute activation of 5-HT(1A) receptors. These findings may provide insight into the long-term heterologous interactions between 5-HT(1A) and 5-HT(2A) receptor signaling that could occur in response to antidepressants, antipsychotics, or drugs of abuse that target these receptor subtypes.
Collapse
Affiliation(s)
- Gonzalo A Carrasco
- Department of Pharmacology, Loyola University of Chicago, Stritch School of Medicine, 2160 S. First Ave., Maywood, IL 60153, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
OBJECTIVE To investigate the effects of acute intravenous (i.v.) delivery of tamsulosin and alfuzosin on the contractions of bulbospongiosus muscles (BS) induced by central delivery of a serotonin agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), in anaesthetized rats, as an experimental model of the expulsion phase of ejaculation. MATERIALS AND METHODS Under urethane anaesthesia, adult male rats were implanted with a cannula into the lateral cerebral ventricle for intracerebroventricular (i.c.v.) injection, and with recording electrodes in the BS for electromyogram (EMG) monitoring. Tamsulosin (1 microg/kg) and alfusozin (10 microg/kg) were injected i.v. and 15 min later 8-OH-DPAT (20 microg) was delivered i.c.v. BS-EMG recording was continued for 30 min after i.c.v. 8-OH-DPAT. The area under the curve (AUC) of the BS cluster of contractions was determined as reflecting the energy of BS contractions. RESULTS After i.c.v. delivery of 8-OH-DPAT, there were rhythmic BS contractions in the form of clusters of bursts in vehicle-, tamsulosin- and alfuzosin-treated rats. The number of BS clusters was not altered by the alpha1-blockers as compared with vehicle, but the AUC was significantly less in tamsulosin-treated rats than in vehicle- or alfuzosin-treated (both P < 0.05) rats. CONCLUSION Systemic injection of tamsulosin impaired BS contractile capacity whereas alfuzosin did not. This might explain anejaculation in men treated with tamsulosin.
Collapse
|
26
|
Stevens KE, O'Neill HC, Rose GM, Luthman J. The 5-HT1A receptor active compounds (R)-8-OH-DPAT and (S)-UH-301 modulate auditory evoked EEG responses in rats. Amino Acids 2006; 31:365-75. [PMID: 16868646 DOI: 10.1007/s00726-006-0374-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Accepted: 03/01/2006] [Indexed: 11/25/2022]
Abstract
Schizophrenics commonly demonstrate abnormalities in central filtering capability following repetitive sensory stimuli. Such sensory inhibition deficits can be mirrored in rodents following administration of psycho-stimulatory drugs. In the present study, male Sprague-Dawley rats were implanted with brain surface electrodes to record auditory evoked EEG potentials in a paired-stimulus paradigm, using 87 dB clicks delivered 0.5 s apart. Amphetamine (1.83 mg/kg, i.p.) produced the expected loss of sensory inhibition, as defined by an increase in the ratio between test (T) and conditioning (C) amplitudes at N40, a mid-latency peak of the evoked potentials. Also, the 5-HT(1A) agonist (R)-8-OH-DPAT caused a significant increase in the TC ratio at the highest dose studied (0.5 mg/kg s.c.), while the 5-HT(1A) antagonist (S)-UH-301 did not significantly affect the TC ratio at any dose studied (0.1-5 mg/kg s.c.). When administered with amphetamine, a lower dose of 8-OH-DPAT (0.1 mg/kg) and the highest dose of UH-301 tested (5 mg/kg, s.c.) were able to reverse the amphetamine-induced increase in TC ratio. The findings suggest that 5-HT(1A) signaling is involved in sensory inhibition and support the evaluation of 5-HT(1A) receptor active compounds in conditions with central filtering deficits, such as schizophrenia.
Collapse
Affiliation(s)
- K E Stevens
- Medical Research, VA Medical Center, Denver, CO, USA
| | | | | | | |
Collapse
|
27
|
Fedotova IO. [Effect of 8-OH-DPAT on the depressive behavior and monoamine metabolism in the hippocampus of ovariectomized rats]. Eksp Klin Farmakol 2006; 69:12-7. [PMID: 16579052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The influence of the chronic administration of the 5-HT1A receptor agonist 8-OH-DPAT (0.05 mg/kg, s.c.) and the 5-HT1A receptor antagonist NAN-190 (0.1 mg/kg, i.p.) alone or in combination with 17beta-estradiol (0.5 microg per animal, i.m.) for 14 days on the depression behavior and the monoamine level in hippocampus has been studied in adult ovariectomized (OVX) female rats. The model of depression in rats was realized under the Porsolt test conditions. The levels of monoamine and its metabolites were determined using HPLC. It was established that the chronic administration of 8-OH-DPAT alone produces an antidepressant effect in OVX rats. The chronic administration of 8-OH-DPAT in combination with 17beta-estradiol potentiated the antidepressant action of both preparations. The antidepressant effect of 8-OH-DPAT in OVX rats was correlated with the restoration of noradrenergic, serotoninergic, and dopaminergic neurotransmission in the hippocampus. The obtained data are indicative of a close interaction between the ovarian hormonal system and the cerebral serotoninergic system in the realization of depression mechanisms.
Collapse
|
28
|
Evrard A, Barden N, Hamon M, Adrien J. Glucocorticoid Receptor-Dependent Desensitization of 5-HT1A Autoreceptors by Sleep Deprivation: Studies in GR-i Transgenic Mice. Sleep 2006; 29:31-6. [PMID: 16453979 DOI: 10.1093/sleep/29.1.31] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
UNLABELLED Sleep deprivation for one night induces mood improvement in depressed patients, an action that probably involves the serotonergic (5-HT) system. In animals, sleep deprivation and pharmacologic treatment with antidepressants exert similar effects on 5-HT neurotransmission, notably functional desensitization of 5-HT1A autoreceptors located on 5-HT neurons in the dorsal raphe nucleus (DRN). However, in stressful conditions, corticosterone can also induce a desensitization of these autoreceptors. STUDY OBJECTIVES To investigate the mechanisms of this adaptation during sleep deprivation and the possible involvement of corticosterone, we studied the effects of an 18-hour sleep deprivation, by forced locomotion, on 5-HT1A receptor-mediated firing response of DRN 5-HT neurons in transgenic mice with impaired glucocorticoid-receptor expression (GR-i) and in wild-type animals. We also examined the effects of chronic treatment with the antidepressant drug fluoxetine in the same paradigm. MEASUREMENTS AND RESULTS In both wild-type and GR-i mice, the 18-hour sleep deprivation or fluoxetine treatment had no effect on the spontaneous firing of 5-HT neurons recorded under anesthesia. However, sleep deprivation decreased the potency of the 5-HT1A agonist 8-OH-DPAT to inhibit 5-HT neuronal firing in wild-type mice, whereas it had no effect in GR-i animals. Conversely, after chronic fluoxetine treatment, the induced reduction of this 5-HT1A autoreceptor-driven response was of larger amplitude in GR-i than in wild-type mice. CONCLUSIONS These data suggest that glucocorticoid-receptor activation by corticosterone participates in the antidepressant-like adaptive changes in 5-HT1A autoreceptors in sleep-deprived mice. On the other hand, GR-i animals exhibited enhanced 5-HT1A autoreceptor desensitization induced by fluoxetine, in line with data in other animal models of depression.
Collapse
Affiliation(s)
- Alexis Evrard
- UMR 677 INSERM-UPMC, Neuropsychopharmacologie, CHUPitié-Salpêtrière, Paris, France
| | | | | | | |
Collapse
|
29
|
Nakamura K, Suzuki K, McCreary AC, Ashby CR. The acute and chronic administration of (±)-8-hydroxy-2-(di-n-propylamino)tetralin significantly alters the activity of spontaneously active midbrain dopamine neurons in rats: An in vivo electrophysiological study. Synapse 2006; 59:359-67. [PMID: 16463399 DOI: 10.1002/syn.20254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the effect of the acute and chronic systemic administration of (+/-)-8-Hydroxy-2-(Di-n-propylamino)Tetralin(8-OH-DPAT) on the number and firing pattern of spontaneously active dopamine (DA) neurons in the ventral tegmental area (VTA or A10) and substantia nigra pars compacta (SNC or A9) in anesthetized male rats. These parameters were measured using extracellular in vivo electrophysiology. A single s.c. injection of 0.01, 0.1, or 1 mg/kg of 8-OH-DPAT did not significantly alter the number of spontaneously active SNC DA neurons compared to vehicle-treated animals (controls). The acute administration of 0.01 or 0.1 mg/kg of 8-OH-DPAT did not significantly alter, whereas the 1 mg/kg dose significantly decreased the number of spontaneously active VTA DA neurons compared to controls. The acute administration of 8-OH-DPAT significantly increased the percentage of VTA DA neurons firing in a bursting pattern. In contrast, there was a significant decrease in the percentage of SNC DA neurons firing in a bursting pattern following the acute administration of 8-OH-DPAT. The number of spontaneously active SNC DA neurons was not significantly altered by the chronic s.c. administration of 8-OH-DPAT (0.01, 0.1, or 1 mg/kg s.c.) as compared to controls. However, the chronic s.c. administration of all doses of 8-OH-DPAT significantly decreased the number of spontaneously active VTA DA neurons compared to controls. The i.v. administration of (+)-apomorphine (50 microg/kg) did not reverse the 8-OH-DPAT-induced decrease in the number of spontaneously active VTA DA neurons, suggesting that this effect is unlikely due to depolarization blockade. The percentage of VTA DA neurons exhibiting burst firing was significantly increased by 0.01 and 0.1 mg/kg, but significantly decreased by 1 mg/kg of 8-OH-DPAT. Overall, the systemic administration of 8-OH-DPAT preferentially affects the activity of spontaneously active A10 DA neurons in rats.
Collapse
Affiliation(s)
- Kazuhiko Nakamura
- Department of Psychiatry, Hamamatsu University School of Medicine 1-20-1, Handayama, Hamamatsu, 431-3192, Shizuoka, Japan
| | | | | | | |
Collapse
|
30
|
De Gobbi JIF, Barbosa SP, De Luca LA, Thunhorst RL, Johnson AK, Menani JV. Activation of serotonergic 5-HT1A receptors in the lateral parabrachial nucleus increases NaCl intake. Brain Res 2005; 1066:1-9. [PMID: 16360657 DOI: 10.1016/j.brainres.2005.04.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Revised: 03/28/2005] [Accepted: 04/01/2005] [Indexed: 11/27/2022]
Abstract
Previous studies using non-specific serotonergic agonists and antagonists have shown the importance of serotonergic inhibitory mechanisms in the lateral parabrachial nucleus (LPBN) for controlling sodium and water intake. In the present study, we investigated whether the serotonergic 5-HT(1A) receptor subtype in the LPBN participates in this control. Male Holtzman rats had cannulas implanted bilaterally into the LPBN. Bilateral injections of the 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.1, 1.25, and 2.5 microg/0.2 microl), into the LPBN enhanced 0.3 M NaCl and water intake of rats injected subcutaneously with the diuretic furosemide (10 mg/kg bw) and a low dose of the angiotensin-converting enzyme inhibitor, captopril (5 mg/kg bw). The increase in NaCl intake produced by 8-OH-DPAT injections was reduced in dose-related manner by pre-treating the LPBN with the selective 5-HT(1A) serotonergic antagonist, WAY-100635 (WAY, 1 and 2 microg/0.2 microl). In contrast, WAY did not affect water intake produced by 8-OH-DPAT. WAY-100635 injected alone into the LPBN had no effect on NaCl ingestion. Injections of 8-OH-DAPT (0.1 microg/0.2 microl) into the LPBN also increased 0.3 M NaCl intake induced by 24-h sodium depletion (furosemide, 20 mg/kg bw plus 24 h of sodium-free diet). Serotonin (5-HT, 20 mug/0.2 mul) injected alone or combined with 8-OH-DPAT into the LPBN reduced 24-h sodium depletion-induced 0.3 M NaCl intake. Therefore, the activation of serotonergic 5-HT(1A) receptors in the LPBN increases stimulated hypertonic NaCl and water intake, while 5-HT injections into the LPBN reduce NaCl intake and prevent the effects of serotonergic 5-HT(1A) receptor activation.
Collapse
Affiliation(s)
- Juliana Irani Fratucci De Gobbi
- Department of Physiology and Pathology, School of Dentistry, Paulista State University (UNESP), Rua Humaitá 1680, 14801-903 Araraquara, SP, Brazil.
| | | | | | | | | | | |
Collapse
|
31
|
Roman V, Walstra I, Luiten PGM, Meerlo P. Too little sleep gradually desensitizes the serotonin 1A receptor system. Sleep 2005; 28:1505-10. [PMID: 16408408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
STUDY OBJECTIVES In our 24-hour society, frequently disrupted and restricted sleep is a rapidly increasing problem that may contribute to the development of diseases such as depression. One of the proposed neurobiological mechanisms underlying depression is a disturbance in the brain's serotonergic neurotransmission, particularly a desensitization of the serotonin (5-HT)1A receptor system. However, a relationship between chronic sleep loss and changes in (5-HT)1A receptors has not been established yet. Therefore, in the present study, we experimentally tested the hypothesis that chronic sleep restriction leads to desensitization of the (5-HT)1A receptor system. DESIGN Rats were subjected to a schedule of restricted sleep allowing them 4 hours of sleep per day. Sleep restriction was achieved by placing the animals in slowly rotating wheels. The sensitivity of the (5-HT)1A receptor system was examined by measuring the hypothermic response to a standard injection of a 1A agonist. RESULTS After 2 days of restricted sleep, the sensitivity of the (5-HT)1A receptor system was not yet affected; however, after 8 days of sleep restriction, it was desensitized. Control experiments indicated that the effect of sleep restriction was not due to forced activity or stress. Importantly, the desensitization of the (5-HT)1A system persisted for many days even with unlimited recovery sleep. Normalization occurred gradually but required at least 7 days. CONCLUSIONS Chronic sleep restriction causes a gradual and persistent desensitization of the (5-HT)1A receptor system. This finding provides a link between chronic sleep loss and sensitivity for disorders that are associated with altered serotonergic neurotransmission.
Collapse
Affiliation(s)
- Viktor Roman
- Department of Molecular Neurobiology, University, of Groningen, Haren, The Netherlands
| | | | | | | |
Collapse
|
32
|
Djavadian RL, Wielkopolska E, Turlejski K. Postnatal treatment with NAN-190 but not with 5-HT1A receptor agonists retards growth of the rat brain. Int J Dev Neurosci 2005; 23:485-93. [PMID: 16026684 DOI: 10.1016/j.ijdevneu.2005.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 01/27/2005] [Accepted: 02/23/2005] [Indexed: 10/25/2022] Open
Abstract
We investigated the influence of prolonged administration of the 5-HT1A receptor agonists (8-OH-DPAT or buspirone) or its antagonist, NAN-190 to rat pups on development of their cortical barrel field. Pups were injected daily with the drugs starting from the day of birth till either the 5th postnatal day or the 22-25th postnatal day and were perfused one day later. Square areas of their whisker barrel fields were measured on tangential sections of the cortex stained for cytochrome oxidase. Injections of 8-OH-DPAT or buspirone till the 5th postnatal day did not change any of the investigated parameters, while injections of NAN-190 resulted in 15% reduction of the pups' body and brain weight and proportional reduction of the square area of their barrel fields. Groups treated till the 22-25th postnatal day showed similar results. Some of these pups were injected with [C(14)]2-deoxyglucose to investigate the strength of responses of their cortical barrels to stimulation of corresponding vibrissae. The cortical area labeled with 2-deoxyglucose after stimulation of vibrissae of the row C was narrower in the NAN-190 injected rats. This functional deficit was more pronounced than the anatomical one, which resembled the effects of neonatal serotonin depletion (Neuroreport, 1997). Therefore, the results of injecting NAN-190 to the rat pups point to a deficit of trophic developmental influences of serotonin, adding new arguments for the hypothesis of a trophic role of 5-HT1A receptors in the brain development.
Collapse
Affiliation(s)
- R L Djavadian
- Nencki Institute of Experimental Biology, Laboratory of Neurobiology of Development and Evolution, 3 Pasteur Street, 02-093 Warsaw, Poland.
| | | | | |
Collapse
|
33
|
Luna-Munguía H, Manuel-Apolinar L, Rocha L, Meneses A. 5-HT1A receptor expression during memory formation. Psychopharmacology (Berl) 2005; 181:309-18. [PMID: 15778876 DOI: 10.1007/s00213-005-2240-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2004] [Accepted: 02/08/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE It has been reported that 5-HT(1A) receptors modulate learning and memory and diverse pharmacological and genetic evidence supports this notion. Nevertheless, there are few works about expression of these receptors during memory formation. OBJECTIVE We aimed to determine 5-HT(1A) receptor expression in brain areas of untrained, passive, and autoshaping trained groups of rats. METHODS Ex vivo receptor autoradiography using the ligand agonist [(3)H]8-hydroxy-2-[di-n-propylamino]tetralin] (8-OH-DPAT) was used. RESULTS The trained group relative to untrained animals showed increases of 5-HT(1A) receptor expression in 14 brain areas, decrements in 7, and no changes in 12. Thus, in contrast to untrained rats, 5-HT(1A) receptor expression of autoshaping trained rats was augmented in the tubercule olfactory, septal nucleus, nucleus accumbens, caudate putamen, globus pallidus, striate, and parietal (1 and 2), temporal cortex (1 and 3), granular retrosplenial cortex (1), amygdala, and median and dorsal raphe nuclei. In contrast, in the latter group, receptors were decreased in the CA1 area, hypothalamus dorsal, frontal cortex (1 and 3), occipital cortex, cingulate cortex (1 and 2), and cuneiform nucleus. There were significant differences between passive vs trained groups, but not regarding untrained rats, in the lateral olfactory tract, dentate gyrus, CA3 area, ventromedial hypothalamic, lateral hypothalamus, preoptic medial, frontal cortex (2), granular retrosplenial cortex (2), entorhinal cortex (1 and 2), piriform cortex, and substantia nigra. CONCLUSIONS These data suggest that upregulated, downregulated, and "silence" of 5-HT(1A) receptors in brain areas form part of neural circuits engaged in memory formation by demonstrating a high degree of specificity and memory mapping.
Collapse
Affiliation(s)
- H Luna-Munguía
- Departo. Farmacobiología, CINVESTAV-IPN, Tenorios 235, Granjas Coapa, México City
| | | | | | | |
Collapse
|
34
|
Visser SAG, Pozarek S, Martinsson S, Forsberg T, Ross SB, Gabrielsson J. Rapid and long-lasting tolerance to clomethiazole-induced hypothermia in the rat. Eur J Pharmacol 2005; 512:139-51. [PMID: 15840398 DOI: 10.1016/j.ejphar.2005.02.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Revised: 02/04/2005] [Accepted: 02/22/2005] [Indexed: 11/19/2022]
Abstract
Mechanism, onset and duration of tolerance development to clomethiazole-induced hypothermia were investigated in rats using telemetry. The hypothermic effect of clomethiazole was completely abolished for 10 days after an s.c. injection of 300 micromol/kg and the effect returned to approximately 50% in 32 days. The gamma-aminobutyric acidA (GABA(A)) receptor agonist muscimol induced hypothermia at 88 micromol/kg without any (cross-) tolerance. GABA(A) receptor antagonists, bicuculline (5.4 micromol/kg) and picrotoxin (3.3 micromol/kg), did not inhibit clomethiazole-induced hypothermia nor the tolerance. The noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, dizocilpine, counteracted clomethiazole-induced hypothermia at 3 micromol/kg but not the tolerance. Tolerance to the 5-hydroxytryptamine(1A) (5-HT(1A)) receptor agonist R-(+)-8-hydroxy-2-(di-n-propylamino)tetralin (R-8-OH-DPAT)-induced hypothermia was blocked by dizocilpine and clomethiazole but not vice versa. No pharmacokinetic interaction was observed. In conclusion, long-lasting tolerance to clomethiazole-induced hypothermia does not involve GABA(A) or 5-HT(1A) receptor functions. Glutamate via NMDA receptors may be involved in the hypothermic response but not in the tolerance.
Collapse
Affiliation(s)
- Sandra A G Visser
- PK/PD section, DMPK&BAC, Local Discovery Research Area CNS & Pain Control, AstraZeneca R&D Södertälje, SE-151 85 Södertälje, Sweden.
| | | | | | | | | | | |
Collapse
|
35
|
Antri M, Barthe JY, Mouffle C, Orsal D. Long-lasting recovery of locomotor function in chronic spinal rat following chronic combined pharmacological stimulation of serotonergic receptors with 8-OHDPAT and quipazine. Neurosci Lett 2005; 384:162-7. [PMID: 15905027 DOI: 10.1016/j.neulet.2005.04.062] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 04/20/2005] [Accepted: 04/23/2005] [Indexed: 11/20/2022]
Abstract
In chronic spinal rats, long-term stimulation of 5-HT receptors with quipazine or 8-OHDPAT by means of daily injection, promotes robust locomotor recovery. The question of a possible potentiation between treatments when applied together was addressed. Daily injections of both 8-OHDPAT and quipazine, were performed for a month in spinal animals. Animals were placed on a treadmill and the bipedal hindlimb locomotion was tested. Motor performances (behavioural test) and locomotor parameters (EMG and kinematic) were analysed weekly during the treatment. Furthermore, the locomotor performances were evaluated during two supplemental months following the end of the treatment. Our results suggest that association of both agonists induced long-lasting positive effects on locomotor function. Motor performances were significantly better after combined injection of both drugs than when the agonists were used separately. But, the most significant and new result is that the locomotor scores did not decrease during the weeks that followed the end of the treatment. These results suggests a long-lasting and 5-HT-dependent reorganisation of spinal networks.
Collapse
Affiliation(s)
- M Antri
- Neurobiologie des Signaux Intercellulaires (NSI), Institut de Biologie Intégrative (IFR 83), Université Pierre et Marie Curie, CNRS UMR 7101, 7 quai Saint Bernard, Boite 002, F-75252 Paris, France
| | | | | | | |
Collapse
|
36
|
Horiuchi J, Wakabayashi S, Dampney RAL. Activation of 5-Hydroxytryptamine 1A Receptors Suppresses the Cardiovascular Response Evoked From the Dorsomedial Hypothalamic Nucleus. Hypertension 2005; 46:173-9. [PMID: 15939808 DOI: 10.1161/01.hyp.0000169970.68151.17] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dorsomedial hypothalamic nucleus is a key component of the central pathways subserving the cardiovascular response to psychological stress, which is believed to be an important risk factor for hypertension. Previous studies indicate that 5-hydroxytryptamine 1A receptors can modulate the cardiovascular responses associated with stress. In this study, we determined in anesthetized rats the effects of systemic or intracisternal administration of 8-hydroxy-2-(di-n-propylamino)tetralin, a selective agonist of 5-hydroxytryptamine 1A receptors, and then subsequent administration of the selective antagonist WAY-100635 on the cardiovascular response evoked by activation of the dorsomedial hypothalamic nucleus (by microinjection of bicuculline). The increase in mean arterial pressure, heart rate, and renal sympathetic nerve activity (RSNA) evoked by bicuculline injection into the dorsomedial hypothalamic nucleus was greatly reduced (by 80% to 90%) by administration of 8-hydroxy-2-(di-n-propylamino)tetralin and then completely restored by subsequent administration of WAY-100635, whether administered systemically or intracisternally. In contrast, systemic administration of 8-hydroxy-2-(di-n-propylamino)tetralin had no significant effect on the baseline level or reflex changes in RSNA evoked by chemoreceptor or baroreceptor stimulation and resulted in only a modest reduction (12 mm Hg) in baseline mean arterial pressure. The results indicate that activation of 5-hydroxytryptamine 1A receptors in the brain stem causes a potent and selective suppression of the hypertensive and sympathoexcitatory response evoked by stimulation of the dorsomedial hypothalamic nucleus but has little effect on the tonic level or baroreceptor or chemoreceptor reflex control of RSNA.
Collapse
Affiliation(s)
- Jouji Horiuchi
- Department of Physiology, Institute for Biomedical Research, The University of Sydney, NSW 2006, Australia
| | | | | |
Collapse
|
37
|
Funk D, Li Z, Fletcher PJ, Lê AD. Effects of injections of 8-hydroxy-2-(di-n-propylamino)tetralin or muscimol in the median raphe nucleus on c-fos mRNA in the rat brain. Neuroscience 2005; 131:475-9. [PMID: 15708488 DOI: 10.1016/j.neuroscience.2004.11.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2004] [Indexed: 11/28/2022]
Abstract
Inhibition of the median raphe nucleus (MRN) by the local injection of 5-HT(1A) or GABA(A) receptor agonists produces strong activational effects on feeding, drinking and locomotor activity. Using an animal model of relapse, we have shown that intra-MRN injection of the 5-HT(1A) autoreceptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) reinstates alcohol seeking in rats. The circuitry underlying the behavioral effects of intra-MRN injection of these drugs is not known. In order to identify the brain areas that may be involved, we measured levels of mRNA of the immediate early gene c-fos in discrete nuclei of the rat brain following intra-MRN infusions of these drugs. Male Wistar rats received intra-MRN infusions of 8-OH-DPAT (1 mug), muscimol (25 ng) or saline vehicle immediately prior to placement in locomotor activity chambers. Thirty minutes later, they were decapitated, and their brains processed for in situ hybridization of c-fos mRNA. In agreement with previous reports, injections of 8-OH-DPAT or muscimol into the MRN resulted in large increases in locomotor activity. Intra-MRN injections of these drugs increased c-fos in a number of brain nuclei previously shown to be involved in the rewarding effects of drugs of abuse in a regionally specific manner. Both drugs significantly increased the expression of c-fos mRNA in the medial frontal cortex, nucleus accumbens, lateral septum, dorsal bed nucleus of the stria terminalis and ventral tegmental area. In the ventral hippocampus, only 8-OH-DPAT increased c-fos, while in the basolateral nucleus of the amygdala and locus coeruleus, it was increased only by muscimol. These results are discussed in terms of the projections of the MRN and the pathways involved in relapse to alcohol and drug seeking.
Collapse
Affiliation(s)
- D Funk
- Department of Neuroscience, Center for Addiction and Mental Health, Toronto, Ontario, Canada M5S 2S1.
| | | | | | | |
Collapse
|
38
|
Tomiyama M, Kimura T, Maeda T, Kannari K, Matsunaga M, Baba M. A serotonin 5-HT1A receptor agonist prevents behavioral sensitization to L-DOPA in a rodent model of Parkinson's disease. Neurosci Res 2005; 52:185-94. [PMID: 15893579 DOI: 10.1016/j.neures.2005.03.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 03/02/2005] [Accepted: 03/10/2005] [Indexed: 11/16/2022]
Abstract
Marked fluctuation of dopamine concentration in the striatum following long-term L-DOPA administration contributes to the development of L-DOPA-induced motor complications including L-DOPA-induced dyskinesias and wearing-off in patients with Parkinson's disease. We have shown that pretreatment with 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A (5-hydroxytryptamine) receptor agonist, alleviates fluctuation of dopamine levels in the dopamine-denervated striatum of 6-hydroxydopamine-lesioned (hemiparkinsonian) rats after L-DOPA treatment. To determine whether co-administration of 8-OH-DPAT with L-DOPA prevents L-DOPA-induced motor complications, we examined rotation behavior and levels of messenger RNAs coding for dynorphin and glutamic acid decarboxylase in the striatum of 6-hydroxydopamine-lesioned rats treated with L-DOPA alone or L-DOPA + 8-OH-DPAT, twice daily, for 2 weeks. Co-administration of 8-OH-DPAT inhibited an increase of rotation behavior to L-DOPA and L-DOPA-induced increases in levels of messenger RNAs coding for dynorphin and glutamic acid decarboxylase in the dopamine-denervated striatum, both of which are established indices of L-DOPA-induced motor complications. These results suggest that pharmaceutical products that stimulate 5-HT1A receptors could prove useful in prevention of the development of L-DOPA-induced motor complications in patients with Parkinson's disease.
Collapse
Affiliation(s)
- Masahiko Tomiyama
- Department of Neurological Science, Institute of Brain Science, Hirosaki University School of Medicine, Hirosaki 036-8562, Japan
| | | | | | | | | | | |
Collapse
|
39
|
Ahn KC, Pazderka-Robinson H, Clements R, Ashcroft R, Ali T, Morse C, Greenshaw AJ. Differential effects of intra-midbrain raphe and systemic 8-OH-DPAT on VTA self-stimulation thresholds in rats. Psychopharmacology (Berl) 2005; 178:381-8. [PMID: 15551069 DOI: 10.1007/s00213-004-2031-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2003] [Accepted: 08/21/2004] [Indexed: 11/30/2022]
Abstract
RATIONALE Intra-median raphe nucleus (MRN) administration of the 5-HT(1A) receptor agonist 8-OH-DPAT decreases lateral hypothalamic self-stimulation thresholds and is reported to have biphasic effects following systemic administration. These experiments attempted to extend the previous findings to mesolimbic pathway self-stimulation at ventral tegmental area (VTA) electrodes. OBJECTIVES This study was conducted to provide comparative data for systemic and intra-dorsal raphe nucleus (DRN) and intra-MRN effects of 8-OH-DPAT on VTA self-stimulation. METHODS Male Sprague-Dawley rats with VTA electrodes were trained to respond for electrical stimulation. Systemic and intra-midbrain raphe 8-OH-DPAT effects on rate-frequency thresholds were measured. Systemic administration of WAY 100635 was used to confirm 5-HT(1A) receptor mediation of 8-OH-DPAT effects. RESULTS 8-OH-DPAT (0.003-0.3 mg kg(-1) SC) increased rate-frequency thresholds and decreased maximal response rates. WAY 100635 alone (0.0125-0.1 mg kg(-1) SC) did not alter these measures. Intra-DRN and intra-MRN 8-OH-DPAT (5.0 microg) decreased rate-frequency thresholds without altering maximal response rates. Intra-DRN 8-OH-DPAT (0.1-5.0 microg) induced a slight decrease and intra-MRN 8-OH-DPAT a slight increase in locomotor activity. WAY 100635 (0.1 mg kg(-1)) blocked effects of 8-OH-DPAT on VTA self-stimulation. CONCLUSION These results confirm threshold-decreasing effects of intra-MRN 8-OH-DPAT and extend this to the DRN and to VTA thresholds. Monophasic dose dependent increases in VTA thresholds following systemic 8-OH-DPAT are not equivalent to reports for hypothalamic self-stimulation. Differences between studies may be attributable to stimulation site and/or differences in threshold measurement procedures. Effects of WAY 100635 in this study indicate 5-HT(1A) receptor mediation of these 8-OH-DPAT effects.
Collapse
Affiliation(s)
- K-C Ahn
- W.G. Dewhurst Laboratories, Department of Psychiatry, 1E7.44 WMC University of Alberta, Edmonton, AB, Canada, T6G 2B7
| | | | | | | | | | | | | |
Collapse
|
40
|
Celik T, Gören MZ, Cinar K, Gürdal H, Onder FO, Tan A, Terzioğlu B, Bozdayi AM, Bozkaya H, Uzunalimoğlu O, Yurdaydin C. Fatigue of cholestasis and the serotoninergic neurotransmitter system in the rat. Hepatology 2005; 41:731-7. [PMID: 15726642 DOI: 10.1002/hep.20617] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Fatigue associated with cholestasis may impair health-related quality of life. The pathogenesis of this symptom is largely unknown, but it has been suggested that central serotoninergic neurotransmission may be implicated and that serotonin 1A receptor agonists may yield improvement. The aim of this study was to study the central serotoninergic system, specifically the serotonin (5-HT)(1A) receptor-mediated pathway of serotoninergic neurotransmission, in a bile duct resection rat model of cholestasis. Fatigue was assessed in the forced swim test in sham and bile duct-resected rats. The serotonin behavioral syndrome, which includes hyperlocomotion, was assessed in both groups of rats after escalating doses of the 5-HT(1A) receptor agonist 8-hydroxy(di-n-propylamine)tetralin (8-OH DPAT). 5-HT(1A) and 5-HT(2) receptor densities were explored in four brain regions using a receptor-binding assay. Extracellular 5-HT and 5-hydroxyindoleacetic acid were measured via in vivo brain dialysis. Bile duct-resected rats spent more time floating in the forced swim test, and 8-OH DPAT decreased floating time in cholestatic rats (P < .01). Dose-response curves created with 8-OH DPAT for the serotonin behavioral syndrome were similar in bile duct-resected and sham-operated rats. 5-HT(1A) and 5-HT(2) receptor densities in most brain regions and extracellular serotonin levels were similar in both groups of rats. In conclusion, 5-HT(1A) receptor agonist-induced amelioration of fatigue in cholestatic rats may be nonspecific and not linked to reversal of the pathophysiology of fatigue associated with cholestasis; however, these data do not exclude a potential role of the central serotoninergic system in the evolution of fatigue.
Collapse
Affiliation(s)
- Turgay Celik
- Department of Medical Pharmacology, Gülhane Military Academy, Ankara, Turkey
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Nalivaiko E, Ootsuka Y, Blessing WW. Activation of 5-HT1A receptors in the medullary raphe reduces cardiovascular changes elicited by acute psychological and inflammatory stresses in rabbits. Am J Physiol Regul Integr Comp Physiol 2005; 289:R596-R604. [PMID: 15802554 DOI: 10.1152/ajpregu.00845.2004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present strategy for the prevention of excessive sympathetic neural traffic to the heart relies on the use of beta-blockers, drugs that act at the heart end of the brain-heart axis. In the present study, we attempted to suppress cardiac sympathetic nerve activity by affecting the relevant cardiomotoneurons in the brain using the selective serotonin-1A (5-HT(1A)) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). In conscious, unrestrained rabbits, instrumented for recordings of heart rate, arterial pressure, or cardiac output, we provoked increases in cardiac sympathetic activity by psychological (loud sound, pinprick, and air jet) or inflammatory (0.5 microg/kg iv lipopolysaccharide) stresses. Pinprick and air-jet stresses elicited transient increases in heart rate (+50 +/- 7 and +38 +/- 4 beats/min, respectively) and in mean arterial pressure (+16 +/- 2 and +15 +/- 3 mmHg, respectively). Lipopolysaccharide injection caused sustained increases in heart rate (from 210 +/- 3 to 268 +/- 10 beats/min) and in arterial pressure (from 74 +/- 3 to 92 +/- 4 mmHg). Systemically administered 8-OH-DPAT (0.004-0.1 mg/kg) substantially attenuated these responses in a dose-dependent manner. Drug effects were prevented by a selective 5-HT(1A) receptor antagonist, WAY-100635 (0.1 mg/kg iv). Similarly to systemic administration, microinjection of 8-OH-DPAT (500 nl of 10 mM solution) into the medullary raphe-parapyramidal region caused antitachycardic effects during stressful stimulation and during lipopolysaccharide-elicited tachycardia. This is the first demonstration that activation of 5-HT(1A) receptors in the medullary raphe-parapyramidal area causes suppression of neurally mediated cardiovascular changes during acute psychological and immune stresses.
Collapse
Affiliation(s)
- Eugene Nalivaiko
- Dept. of Human Physiology, Centre for Neuroscience and Flinders Medical Centre, Flinders University, Bedford Park, 5042 SA, Australia.
| | | | | |
Collapse
|
42
|
Nugroho AK, Li L, Dijkstra D, Wikström H, Danhof M, Bouwstra JA. Transdermal iontophoresis of the dopamine agonist 5-OH-DPAT in human skin in vitro. J Control Release 2005; 103:393-403. [PMID: 15763622 DOI: 10.1016/j.jconrel.2004.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 12/04/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
The feasibility of transdermal iontophoretic delivery of a potent dopamine agonist 5-OH-DPAT was studied in vitro in side by side diffusion cells across human stratum corneum (HSC) and dermatomed human skin (DHS) according to the following protocol: 6 h of passive diffusion, 9 h of iontophoresis and 5 h of passive diffusion. The influences of the following parameters on the flux were studied: donor solution pH, NaCl concentration, drug donor concentration, current density and skin type. A current density of 0.5 mA cm(-2) was used, except for one series of experiments to study the current density effect. Probably due to the influence of the skin perm-selectivity and the competition with H(+), increase in pH from 3 to 5 resulted in a significant increase in flux. Further increase in pH to 6 did not further increase the flux. The iontophoretic transport was found to increase linearly with concentration and current density, providing a convenient way to manage dose titration for Parkinson's disease therapy. Increase in concentration of NaCl dramatically reduced the flux of 5-OH-DPAT as a result of ion competition to the transport. When DHS was used, the iontophoretic transport was less. Also, with DHS the response in flux profile, by switching the current on and off, was shallower than that with HSC. With the optimum condition, a delivery of 104 microg of 5-OH-DPAT per cm(2) patch per hour is feasible, indicating that the therapeutic level could be achieved with a smaller patch size than required in case of rotigotine. Thus, based on this in vitro study, transdermal iontophoretic delivery of 5-OH-DPAT is very promising.
Collapse
Affiliation(s)
- Akhmad Kharis Nugroho
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, University of Leiden, PO Box 9502, 2300 RA Leiden, The Netherlands
| | | | | | | | | | | |
Collapse
|
43
|
Häckl LPN, de Oliveira Richter G, Serralvo Faria M, Paschoalini MA, Marino-Neto J. Behavioral effects of 8-OH-DPAT injections into pontine and mesencephalic areas containing 5-HT-immunoreactive perikarya in the pigeon. Brain Res 2005; 1035:154-67. [PMID: 15722055 DOI: 10.1016/j.brainres.2004.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 10/28/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
This study examined the distribution of 5-HT-immunoreactive perikarya (5-HT-IRp) and the effects of local injections of 8-OH-DPAT into 5-HT-IRp-containing pontine and mesencephalic regions on feeding and drinking behaviors in free-feeding pigeons. When infused into the midline 5-HT-IRp-containing areas, 8-OH-DPAT (6.1 nmol) reliably elicited drinking and, to a lesser extent, feeding responses during the first hour after injection. These responses were significantly higher than the ingestive indexes observed (1) after vehicle (ascorbic acid 0.1%, 200 nl) injections at the same sites and (2) after 8-OH-DPAT injections into adjacent sites devoid of 5-HT-IRp. Increases in drinking were proportionally higher than those observed in feeding and a significant negative correlation was observed between water and food after midline 8-OH-DPAT injections. Similar dipsogenic responses were observed after injections of different 8-OH-DPAT doses (0.6, 2.0, and 6.1 nmol). Pretreatment with local injections of p-MPPI (an antagonist of 5-HT1A receptors) attenuated the ingestive responses evoked by 8-OH-DPAT injections. Injections of 8-OH-DPAT into lateral 5-HT-IRp-containing sites evoked only inconsistent and weak ingestive responses. These results indicate that 5-HT1A receptor-mediated circuits located in the midline superior raphe system of the pigeon may play an important role in mechanisms controlling water intake, similar to that observed in mammals.
Collapse
Affiliation(s)
- Luciane P N Häckl
- Department of Physiological Sciences-CCB, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | | | | | | | | |
Collapse
|
44
|
Idova GV, Cheĭdo MA, Davydova SM. [Activation and blocking of 5-HT1A receptors influence on the immune response in CBA mice]. Eksp Klin Farmakol 2005; 68:42-4. [PMID: 15786964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
5-HT1A type serotonin receptors influence the immunomodulating action of the selective preparations 8-OH-DPAT (5-HT1A receptor agonist) and WAY-100635 (5-HT1A receptor antagonist) in CBA mice. The activation of 5HT1A receptors with 8-OH-DPAT (1 mg/kg) decreased, while their blocking with WAY-100635 (1 mg/kg) increased the reaction intensity at the peak of response to immunization with ram erythrocytes. Preliminary blocking of the 5-HT1A receptors with WAY-100635 prevented the inhibiting action of 8-OH-DPAT.
Collapse
|
45
|
Moreira FA, Guimarães FS. Benzodiazepine receptor and serotonin 2A receptor modulate the aversive-like effects of nitric oxide in the dorsolateral periaqueductal gray of rats. Psychopharmacology (Berl) 2004; 176:362-8. [PMID: 15278346 DOI: 10.1007/s00213-004-1910-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 04/14/2004] [Indexed: 11/28/2022]
Abstract
RATIONALE Escape reactions induced by electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) are inhibited by local administration of benzodiazepine (BZ) or serotonin (5-HT) receptor agonists. Nitric oxide (NO) is a gas messenger that may mediate aversive behaviors. NO donors injected into the dlPAG induce escape reactions. OBJECTIVES To test the hypothesis that the escape reactions induced by a NO donor in the dlPAG would be attenuated by pre-treatment with BZ-receptor or 5-HT-receptor agonists. METHODS Male Wistar rats with cannulae aimed at the dlPAG received microinjections of vehicle (0.2 microl), the BZ midazolam maleate (80 nmol), the 5-HT(1A)-receptor agonist 8-OH-DPAT (8 nmol or 16 nmol) or the 5-HT(2A/2C)-receptor agonist DOI (16 nmol) 10 min before the administration of the NO donor SIN-1 (150 nmol). Behavioral observation took place immediately after the last injection in an open arena over a 10-min period. RESULTS SIN-1 induced escape reactions characterized by running and jumps. Pre-treatment with DOI, but not 8-OH-DPAT, partially inhibited the effects of SIN-1. Pre-treatment with midazolam maleate, however, completely prevented the effects of the NO donor. CONCLUSION The results suggest that the aversive-like effects of NO donor in the dlPAG may be modulated by the BZ and 5-HT(2A/2C) receptors.
Collapse
|
46
|
Beyer CE, Ghavami A, Lin Q, Sung A, Rhodes KJ, Dawson LA, Schechter LE, Young KH. Regulators of G-protein signaling 4: modulation of 5-HT1A-mediated neurotransmitter release in vivo. Brain Res 2004; 1022:214-20. [PMID: 15353231 DOI: 10.1016/j.brainres.2004.06.073] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2004] [Indexed: 11/30/2022]
Abstract
Regulators of G-protein signaling (RGS) play a key role in the signal transduction of G-protein-coupled receptors (GPCRs). Specifically, RGS proteins function as GTPase accelerating proteins (GAPs) to dampen or "negatively regulate" GPCR-mediated signaling. Our group recently showed that RGS4 effectively GAPs Galpha(i)-mediated signaling in CHO cells expressing the serotonin-1A (5-HT(1A)) receptor. However, whether a similar relationship exists in vivo has yet to be identified. In present studies, a replication-deficient herpes simplex virus (HSV) was used to elevate RGS4 mRNA in the rat dorsal raphe nuclei (DRN) while extracellular levels of 5-HT in the striatum were monitored by in vivo microdialysis. Initial experiments conducted with noninfected rats showed that acute administration of 8-OH-DPAT (0.01-0.3 mg/kg, subcutaneous [s.c.]) dose dependently decreased striatal levels of 5-HT, an effect postulated to result from activation of somatodendritic 5-HT(1A) autoreceptors in the DRN. In control rats receiving a single intra-DRN infusion of HSV-LacZ, 8-OH-DPAT (0.03 mg/kg, s.c.) decreased 5-HT levels to an extent similar to that observed in noninfected animals. Conversely, rats infected with HSV-RGS4 in the DRN showed a blunted neurochemical response to 8-OH-DPAT (0.03 mg/kg, s.c.); however, increasing the dose to 0.3 mg/kg reversed this effect. Together, these findings represent the first in vivo evidence demonstrating that RGS4 functions to GAP Galpha(i)-coupled receptors and suggest that drug discovery efforts targeting RGS proteins may represent a novel mechanism to manipulate 5-HT(1A)-mediated neurotransmitter release.
Collapse
Affiliation(s)
- Chad E Beyer
- Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, NJ 08543-8000, USA.
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Tada M, Shirakawa K, Matsuoka N, Mutoh S. Combined treatment of quetiapine with haloperidol in animal models of antipsychotic effect and extrapyramidal side effects: comparison with risperidone and chlorpromazine. Psychopharmacology (Berl) 2004; 176:94-100. [PMID: 15083255 DOI: 10.1007/s00213-004-1866-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Accepted: 03/03/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE Quetiapine, an atypical neuroleptic, has beneficial antipsychotic effects in schizophrenic patients, but with a lower incidence of extrapyramidal symptoms (EPS) compared with typical antipsychotics. While typical antipsychotics are often switched to atypical agents when adverse effects become limiting, there is little preclinical information to support this strategy, both in terms of efficacy and side effects. OBJECTIVES The antipsychotic effects and EPS during concomitant administration of quetiapine with haloperidol, a typical antipsychotic agent, were evaluated in mice and compared with chlorpromazine and risperidone. METHODS We first investigated the antipsychotic effects and EPS liability of quetiapine, risperidone, chlorpromazine, and haloperidol when administered alone to select optimal doses for subsequent combination studies. The second study was designed to evaluate the antipsychotic efficacy and EPS profile of concomitant administration of quetiapine, risperidone, or chlorpromazine with haloperidol. Antipsychotic effects were evaluated with the methamphetamine-induced hyperlocomotion test, and EPS liability was evaluated in a catalepsy-induction model. RESULTS Quetiapine, risperidone, chlorpromazine, and haloperidol dose-dependently reduced methamphetamine-induced hyperlocomotion, with ED50 values of 5.6, 0.020, 1.8, 0.035 mg/kg, respectively. In the catalepsy test, quetiapine only weakly induced catalepsy at the highest dose of 100 mg/kg, whereas risperidone, chlorpromazine, and haloperidol dose-dependently induced catalepsy with ED50 values of 0.25, 4.6, and 0.10 mg/kg, respectively. While the combination of quetiapine (6 mg/kg) and haloperidol (0.04 mg/kg) significantly reduced methamphetamine-induced hyperlocomotion in comparison with haloperidol alone, quetiapine (10, 32 mg/kg) plus haloperidol did not potentiate the cataleptogenic activity of haloperidol. In contrast, risperidone (0.1, 0.32 mg/kg) or chlorpromazine (3.2 mg/kg) significantly augmented catalepsy induced by haloperidol. Catalepsy induced by co-administration of quetiapine (10 mg/kg) and haloperidol (0.1 mg/kg) was significantly potentiated by WAY100635, a 5-HT1A antagonist, and catalepsy induced by co-administration of risperidone (0.1 mg/kg) and haloperidol (0.1 mg/kg) was significantly antagonized by 8-OH-DPAT, a 5-HT1A agonist. CONCLUSION The present study demonstrated that the combined administration of quetiapine with haloperidol did not aggravate EPS, possibly because of its affinity for 5-HT1A receptors. This finding may have the clinical implication that quetiapine could provide a successful regimen in switching from typical antipsychotic agents in the symptom management of schizophrenia, or even in adjunctive therapy with other antipsychotic agents.
Collapse
Affiliation(s)
- Miho Tada
- Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co. Ltd, 2-1-6 Kashima, Yodogawa-ku, Osaka, 532-8514, Japan
| | | | | | | |
Collapse
|
48
|
Szumlinski KK, Frys KA, Kalivas PW. Dissociable roles for the dorsal and median raphé in the facilitatory effect of 5-HT1A receptor stimulation upon cocaine-induced locomotion and sensitization. Neuropsychopharmacology 2004; 29:1675-87. [PMID: 15127081 DOI: 10.1038/sj.npp.1300473] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A distinct role for serotonin transmission from the dorsal and median raphé nuclei (DRN and MRN, respectively) was identified in regulating the behavioral and neurochemical effects of acute and repeated cocaine administration. Serotonin 1A (5-hydroxytryptophan (5-HT)1A) receptors were stimulated by intraraphé microinjection of 8-hydroxy-2-(di-n-propylamino)tetralin (DPAT; 5 or 10 microg) and behavior, as well as extracellular neurotransmitter content in the nucleus accumbens was measured. Pretreatment of the DRN with DPAT caused a sensitization-like potentiation of acute cocaine-induced motor activity and an elevation in extracellular dopamine and glutamate. In contrast, DPAT microinjection into the MRN did not alter acute cocaine-induced motor activity or extracellular levels of dopamine or glutamate. Acutely, DPAT microinjection into either raphé nucleus reduced the basal and acute cocaine-stimulated levels of extracellular serotonin. Pretreatment with DPAT before systemic cocaine administration was continued for 5 days, and 3 weeks after the last injection, all rats were administered a cocaine challenge injection. The sensitized behavioral and neurochemical response produced by repeated cocaine in control subjects was unaffected by the intra-DRN administration of DPAT. However, in animals administered DPAT into the MRN, both the sensitized motor response and the increase in glutamate were augmented, while the sensitized serotonin response was blocked, without altering dopamine sensitization. These data show a differential role for 5-HT1A receptors in the DRN and MRN in the acute and sensitized effects of cocaine. While the DRN is involved in the acute effects of cocaine, neuroadaptations in the MRN may regulate the long-term consequences of repeated cocaine exposure.
Collapse
Affiliation(s)
- Karen K Szumlinski
- Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA.
| | | | | |
Collapse
|
49
|
Yu Y, Ramage AG, Koss MC. Pharmacological studies of 8-OH-DPAT-induced pupillary dilation in anesthetized rats. Eur J Pharmacol 2004; 489:207-13. [PMID: 15087245 DOI: 10.1016/j.ejphar.2004.03.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Revised: 02/02/2004] [Accepted: 03/02/2004] [Indexed: 11/17/2022]
Abstract
Serotonin (5-HT)(1A) receptor agonists have been reported to produce mydriasis in mice, and miosis in rabbits and humans. However, the underlying mechanisms for this action are unclear. This study was undertaken in an attempt to explore the mechanism by which 5-HT(1A) receptors are involved in the modulation of pupillary size in pentobarbital-anesthetized rats. Intravenous administration of the 5-HT(1A) receptor agonist, (2R)-(+)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT; 0.003-3 mg/kg), elicited dose-dependent pupillary dilation, which was not affected by section of the preganglionic cervical sympathetic nerve. 8-OH-DPAT-elicited mydriatic responses were attenuated by the selective 5-HT(1A) receptor antagonist, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide maleate (WAY 100635; 0.3-1 mg/kg, i.v.), as well as by the selective alpha(2)-adrenoceptor antagonist, (8aR,12aS,13aS)-5,8,8a,9,10,11,12,12a,13,13a-dechydro-3-methoxy-12-(ethylsulfonyl)-6H-isoquino[2,1-g][1,6]naphthyridine hydrochloride (RS 79948; 0.3 mg/kg, i.v.), but not by the selective alpha(1)-adrenoceptor antagonist, prazosin (0.3 mg/kg, i.v.). Mydriatic responses elicited by the alpha(2)-adrenoceptor agonist, guanabenz (0.003-0.3 mg/kg, i.v.), were not antagonized by WAY 100635 (0.3-1 mg/kg, i.v.). To determine whether central nervous system (CNS) 5-HT(1A) receptors, like alpha(2)-adrenoceptors, are involved in reflex mydriasis, voltage response curves of pupillary dilation were constructed by stimulation of the sciatic nerve in anesthetized rats. WAY 100635 (1 mg/kg, i.v.) did not antagonize the evoked reflex mydriasis, which, however, was blocked by RS 79948 (0.3 mg/kg, i.v.). Taken together, these results suggest that 8-OH-DPAT produces pupillary dilation in anesthetized rats by stimulating CNS 5-HT(1A) receptors, which in turn trigger the release of norepinephrine, presumably from the locus coeruleus. The latter reduces parasympathetic neuronal tone to the iris sphincter muscle by stimulation of postsynaptic alpha(2)-adrenoceptors within the Edinger-Westphal nucleus. Unlike alpha(2)-adrenoceptors, 5-HT(1A) receptors in the CNS do not mediate reflex mydriasis evoked by sciatic nerve stimulation.
Collapse
MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/administration & dosage
- 8-Hydroxy-2-(di-n-propylamino)tetralin/antagonists & inhibitors
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacokinetics
- Adrenergic alpha-2 Receptor Antagonists
- Animals
- Dose-Response Relationship, Drug
- Electric Stimulation
- Guanabenz/pharmacology
- Injections, Intravenous
- Isoquinolines/pharmacology
- Male
- Mydriasis/chemically induced
- Mydriasis/prevention & control
- Naphthyridines/pharmacology
- Piperazines/pharmacology
- Pupil/drug effects
- Pupil/physiology
- Pyridines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/administration & dosage
- Receptor, Serotonin, 5-HT1A/physiology
- Receptors, Adrenergic, alpha-2/administration & dosage
- Receptors, Adrenergic, alpha-2/physiology
- Sciatic Nerve/pathology
- Sciatic Nerve/physiology
- Serotonin 5-HT1 Receptor Antagonists
Collapse
Affiliation(s)
- Yongxin Yu
- Department of Cell Biology, University of Oklahoma College of Medicine, Oklahoma City, OK 73190, USA.
| | | | | |
Collapse
|
50
|
Yoshitake T, Kehr J. Differential effects of (R)-, (R, S)- and (S)-8-hydroxy-2-(di-n-propylamino)tetralin on hippocampal serotonin release and induction of hypothermia in awake rats. Life Sci 2004; 74:2865-75. [PMID: 15050424 DOI: 10.1016/j.lfs.2003.10.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2003] [Accepted: 10/14/2003] [Indexed: 10/26/2022]
Abstract
The effects of (R)- and (S)-optical isomers of 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) and of the racemate (R,S)-8-OH-DPAT on serotonin (5-HT) release in the ventral hippocampus of awake rats and on induction of the whole-body hypothermia were studied. Extracellular 5-HT levels were determined by a newly developed high-sensitive HPLC method based on derivatization with benzylamine and fluorescence detection. The basal levels of 5-HT in 20 min microdialysates from rats perfused with Ringer solution or with Ringer solution containing 1 microM citalopram were 6.3 +/- 1.3 fmol/20 microl and 36.1 +/- 4.2 fmol/20 microl (n=20), respectively. The reduction of hippocampal 5-HT levels induced by subcutaneous (s.c.) administration of (R,S)-8-OH-DPAT (0.3 mg/kg) was significantly attenuated by the presence of 5-HT reuptake inhibitor citalopram in Ringer solution only at its peak value at 40 min (maximal reduction to 60% compared to 46% of control values in Ringer-perfused rats), whereas the overall effects were comparable at both experimental conditions. Injection of (R)-8-OH-DPAT (0.3 mg/kg s.c.) caused further reduction of 5-HT levels, to 49% and 41%, respectively, whereas (S)-8-OH-DPAT (0.3 mg/kg s.c.) caused maximal reduction of 5-HT levels only to 74% of controls in both perfusion groups. Similar pattern and time-courses were observed in rats with hypothermia induced by injection of 8-OH-DPAT enantiomers, where (R,S), (R)-forms were about two-times more potent than the (S)-isomer. It is concluded that the acute systemic dose of (R)-, (S)- and (R,S)-8-OH-DPAT enantiomers exerted enantiomer-specific effects on 5-HT(1A) receptor-mediated function both at the presynaptic and postsynaptic sites as revealed by monitoring hippocampal 5-HT levels and body temperature.
Collapse
Affiliation(s)
- Takashi Yoshitake
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | | |
Collapse
|