1
|
Islam MZ, Wu S, Ootawa T, Smith H, Nguyen HTT, Harada E, Miyamoto A. Characteristics of Cerebrovascular Response to Intrinsic Vasoactive Substances in Sika Deer ( Cervus nippon yesoensis) and the Possible Effects of Gravity on Adrenergic Responses. Animals (Basel) 2024; 14:3500. [PMID: 39682465 DOI: 10.3390/ani14233500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2024] [Revised: 11/27/2024] [Accepted: 12/02/2024] [Indexed: 12/18/2024] Open
Abstract
Gravity may exert species-specific effects on quadrupedal vasoreactivity, reflecting variations in the vertical displacement of the cardiocranial axis from the dorsal plane. Deer show markedly displaced cardiocranial axes compared to their closest phylogenetic relatives, but their relative cerebrovascular responses remain unelucidated. Accordingly, we investigated the responses to noradrenaline (NA), acetylcholine (ACh), 5-hydroxytryptamine (5-HT), histamine, angiotensin (Ang) II, and bradykinin (BK) in cervine basilar arterial rings. NA and 5-HT induced slight contraction, and ACh induced relaxation, which contrasts with the findings reported in pigs and cattle. The cumulative response to ACh was abolished by endothelial denudation and inhibited by Nω-nitro-L-arginine (a nitric oxide synthase inhibitor), atropine (a nonselective muscarinic antagonist), and p-fluoro-hexahydro-sila-difenidol (an M3 antagonist). Pirenzepine (an M1 antagonist) and methoctramine (an M2 antagonist) showed no significant effects. Histamine induced contractions, with its concentration-response curve shifted to the right in parallel by diphenhydramine (an H1 antagonist). However, cimetidine (an H2 antagonist) showed no significant effects. Ang II and BK had no vasomotive effects. NA and ACh induced different cerebrovascular responses in sika deer versus cattle, but histamine and BK did not. Our findings suggest that cerebrovascular responses are influenced by the similarity of animal species and the head and heart positions relative to gravity.
Collapse
Affiliation(s)
- Md Zahorul Islam
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Department of Pharmacology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Siyuan Wu
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Tomoki Ootawa
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Henry Smith
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Ha Thi Thanh Nguyen
- Department of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Gia Lam, Hanoi 131000, Vietnam
| | - Etsumori Harada
- Department of Veterinary Physiology, Faculty of Agriculture, Tottori University, 4-101 Minami, Koyama-cho, Tottori 680-8553, Japan
| | - Atsushi Miyamoto
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| |
Collapse
|
2
|
Biringer RG. Migraine signaling pathways: amino acid metabolites that regulate migraine and predispose migraineurs to headache. Mol Cell Biochem 2022; 477:2269-2296. [PMID: 35482233 DOI: 10.1007/s11010-022-04438-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/08/2022] [Indexed: 10/18/2022]
Abstract
Migraine is a common, debilitating disorder for which attacks typically result in a throbbing, pulsating headache. Although much is known about migraine, its complexity renders understanding the complete etiology currently out of reach. However, two important facts are clear, the brain and the metabolism of the migraineur differ from that of the non-migraineur. This review centers on the altered amino acid metabolism in migraineurs and how it helps define the pathology of migraine.
Collapse
Affiliation(s)
- Roger Gregory Biringer
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, Bradenton, FL, 34211, USA.
| |
Collapse
|
3
|
Da Costa Guevara D, Trejo E. 5-HT 2A, 5-HT 1B/D, 5HT 3 and 5-HT 7 receptors as mediators of serotonin-induced direct contractile response of bovine airway smooth muscle. J Smooth Muscle Res 2022; 57:79-93. [PMID: 34980821 PMCID: PMC8710915 DOI: 10.1540/jsmr.57.79] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Serotonin (5-hydroxytryptamine; 5-HT) performs a variety of functions in the
body including the modulation of muscle tone in respiratory airways. Several studies
indicate a possible role of 5-HT in the pathophysiology of bronchial hyperresponsiveness.
However, the receptors and the molecular mechanisms by which 5-HT acts on airway smooth
muscle (ASM) continue to be controversial. Most of the evidence suggests the participation
of different subtypes of receptors in an indirect response. This study supports the
proposal that 5-HT directly contracts ASM and characterizes pharmacologically the subtypes
of serotonergic receptors involved. The characterization was carried out by using
selective antagonists in an organ bath model allowing study of the smooth muscle of
segments of bovine trachea. Results: The results obtained show that 5-HT2A
receptors are the main mediators of the direct contractile response of bovine ASM, with
the cooperation of the 5-HT7, 5-HT3 and 5-HT1B/D
receptors. Also, it was observed that the muscle response to serotonin is developed more
slowly and to a lesser extent in comparison with the response to cholinergic stimulation.
Conclusion: Overall, the receptors that mediate the direct serotonergic contraction of the
smooth muscle of the bovine trachea are 5-HT2A, 5-HT7,
5-HT3 and 5-HT1B/D receptors.
Collapse
Affiliation(s)
- Darwin Da Costa Guevara
- Sección de Biomembranas, Instituto de Medicina Experimental (IME), Facultad de Medicina, Universidad Central de Venezuela (UCV), Caracas, Venezuela
| | - Ernesto Trejo
- Sección de Biomembranas, Instituto de Medicina Experimental (IME), Facultad de Medicina, Universidad Central de Venezuela (UCV), Caracas, Venezuela
| |
Collapse
|
4
|
Yesildal F, Doganci S, Yildirim V, Ozgurtas T. Stimulation of 5-Hydroxytriptamine 7 Receptor by LP-211 Boosts Angiogenic Response. INT J PHARMACOL 2020. [DOI: 10.3923/ijp.2020.98.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
5
|
Quintero-Villegas A, Valdés-Ferrer SI. Role of 5-HT 7 receptors in the immune system in health and disease. Mol Med 2019; 26:2. [PMID: 31892309 PMCID: PMC6938607 DOI: 10.1186/s10020-019-0126-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023] Open
Abstract
In mammalians, serotonin (5-HT) has critical roles in the central nervous system (CNS), including mood stability, pain tolerance, or sleep patterns. However, the vast majority of serotonin is produced by intestinal enterochromaffin cells of the gastrointestinal tract and circulating blood platelets, also acting outside of the CNS. Serotonin effects are mediated through its interaction with 5-HT receptors (5-HTRs), a superfamily with a repertoire of at least fourteen well-characterized members. 5-HT7 receptors are the last 5-HTR member to be identified, with well-defined functions in the nervous, gastrointestinal, and vascular systems. The effects of serotonin on the immune response are less well understood. Mast cells are known to produce serotonin, while T cells, dendritic cells, monocytes, macrophages and microglia express 5-HT7 receptor. Here, we review the known roles of 5-HT7 receptors in the immune system, as well as their potential therapeutic implication in inflammatory and immune-mediated disorders.
Collapse
Affiliation(s)
- Alejandro Quintero-Villegas
- Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico
- Department of Medicine, Intituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, Mexico
| | - Sergio Iván Valdés-Ferrer
- Departments of Neurology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
- Departments of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
- Center for Biomedical Science, Feinstein Institute for Medical Research, Manhasset, NY, USA.
| |
Collapse
|
6
|
Thirumaran SL, Lepailleur A, Rochais C. Structure-activity relationships of serotonin 5-HT7 receptors ligands: A review. Eur J Med Chem 2019; 183:111705. [DOI: 10.1016/j.ejmech.2019.111705] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 01/30/2023]
|
7
|
Snider MA, Harmon DL, Klotz JL. Pharmacologic assessment of bovine ruminal and mesenteric vascular serotonin receptor populations. J Anim Sci 2018; 96:1570-1578. [PMID: 29471490 DOI: 10.1093/jas/sky038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/15/2018] [Indexed: 11/12/2022] Open
Abstract
Prior work using a contractility bioassay determined that the serotonin (5-HT) receptor subtype 5-HT2A is present in bovine lateral saphenous veins and plays a role in ergot alkaloid (EA)-induced vascular contraction in steers grazing endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum). Ergot alkaloids have also been shown to be vasoactive in bovine gut vasculature. To determine what 5-HT receptors are involved in vasoconstriction of gut vasculature, contractility of ruminal and mesenteric arteries and veins collected from cattle was evaluated in the presence of agonists selective for 5-HT1B (CP 93129), 5-HT1D (L-694, 247), 5-HT2A (TCB-2), 5-HT2B (BW 723C86), 5-HT4 (BIMU-8), and 5-HT7 (LP 44) receptors. Segments of ruminal and mesenteric veins and arteries were collected and suspended in a multimyograph containing continuously oxygenated Krebs-Henseleit buffer. Blood vessels were exposed to increasing concentrations of 5-HT agonists every 15 min and contractile response data were normalized as a percentage of the maximum contractile response induced by 120 mM KCl. Analysis of variance was evaluated using mixed models procedure of SAS for effects of agonist concentration for each vessel type. Receptor agonists for 5-HT2B, 5-HT1D, and 5-HT7 did not induce a contractile response for ruminal or mesenteric vasculature (P > 0.05). However, when exposed to agonists for 5-HT2B or 5-HT1D, mesenteric veins relaxed below zero (P < 0.05). Exposure of all 4 blood vessel types to 5-HT2A agonist induced contractile responses (P < 0.05). The findings of this study indicate that 5-HT1D and 5-HT2B are present in mesenteric veins and may play a role in vasorelaxation. Further, 5-HT2A is present in ruminal and mesenteric vasculature, plays a role in vasoconstriction of these vessels, and could be influenced by EA exposure as has been demonstrated in peripheral blood vessels.
Collapse
Affiliation(s)
- Miriam A Snider
- Department of Animal and Food Science, University of Kentucky, Lexington, KY
| | - David L Harmon
- Department of Animal and Food Science, University of Kentucky, Lexington, KY
| | - James L Klotz
- USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY
| |
Collapse
|
8
|
Rizvić E, Janković G, Savić MM. Elucidation of the profound antagonism of contractile action of phenylephrine in rat aorta effected by an atypical sympathomimetic decongestant. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:385-395. [PMID: 28706452 PMCID: PMC5507777 DOI: 10.4196/kjpp.2017.21.4.385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/07/2017] [Accepted: 04/07/2017] [Indexed: 11/15/2022]
Abstract
Vasoconstrictive properties of sympathomimetic drugs are the basis of their widespread use as decongestants and possible source of adverse responses. Insufficiently substantiated practice of combining decongestants in some marketed preparations, such are those containing phenylephrine and lerimazoline, may affect the overall contractile activity, and thus their therapeutic utility. This study aimed to examine the interaction between lerimazoline and phenylephrine in isolated rat aortic rings, and also to assess the substrate of the obtained lerimazoline-induced attenuation of phenylephrine contraction. Namely, while lower concentrations of lerimazoline (10−6 M and especially 10−7 M) expectedly tended to potentiate the phenylephrine-induced contractions, lerimazoline in higher concentrations (10−4 M and above) unexpectedly and profoundly depleted the phenylephrine concentration-response curve. Suppression of NO with NO synthase (NOS) inhibitor Nw-nitro-L-arginine methyl ester (L-NAME; 10−4 M) or NO scavanger OHB12 (10−3 M), as well as non-specific inhibition of K+-channels with tetraethylammonium (TEA; 10−3 M), have reversed lerimazoline-induced relaxation of phenylephrine contractions, while cyclooxygenase inhibitor indomethacin (10−5 M) did not affect the interaction between two vasoconstrictors. At the receptor level, non-selective 5-HT receptor antagonist methiothepin reversed the attenuating effect of lerimazoline on phenylephrine contraction when applied at 3×10−7 and 10−6 M, but not at the highest concentration (10−4 M). Neither the 5-HT1D-receptor selective antagonist BRL 15572 (10−6 M) nor 5-HT7 receptor selective antagonist SB 269970 (10−6 M) affected the lerimazoline-induced attenuation of phenylephrine activity. The mechanism of lerimazoline-induced suppression of phenylephrine contractions may involve potentiation of activity of NO and K+-channels and activation of some methiothepin-sensitive receptors, possibly of the 5-HT2B subtype.
Collapse
Affiliation(s)
- Eldina Rizvić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Goran Janković
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Miroslav M Savić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| |
Collapse
|
9
|
Seitz BM, Orer HS, Krieger-Burke T, Darios ES, Thompson JM, Fink GD, Watts SW. 5-HT causes splanchnic venodilation. Am J Physiol Heart Circ Physiol 2017. [PMID: 28626072 DOI: 10.1152/ajpheart.00165.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg-1·min-1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure.NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.
Collapse
Affiliation(s)
- Bridget M Seitz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Hakan S Orer
- Department of Pharmacology, School of Medicine, Koc University, Istanbul, Turkey
| | - Teresa Krieger-Burke
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Emma S Darios
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| |
Collapse
|
10
|
Low-basicity 5-HT 7 Receptor Agonists Synthesized Using the van Leusen Multicomponent Protocol. Sci Rep 2017; 7:1444. [PMID: 28473721 PMCID: PMC5431432 DOI: 10.1038/s41598-017-00822-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/14/2017] [Indexed: 12/12/2022] Open
Abstract
A series of 5-aryl-1-alkylimidazole derivatives was synthesized using the van Leusen multicomponent reaction. The chemotype is the first example of low-basicity scaffolds exhibiting high affinity for 5-HT7 receptor together with agonist function. The chosen lead compounds 3-(1-ethyl-1H-imidazol-5-yl)-5-iodo-1H-indole (AGH-107, 1o, Ki 5-HT7 = 6 nM, EC50 = 19 nM, 176-fold selectivity over 5-HT1AR) and 1e (5-methoxy analogue, Ki 5-HT7 = 30 nM, EC50 = 60 nM) exhibited high selectivity over related CNS targets, high metabolic stability and low toxicity in HEK-293 and HepG2 cell cultures. A rapid absorption to the blood, high blood-brain barrier permeation and a very high peak concentration in the brain (Cmax = 2723 ng/g) were found for 1o after i.p. (5 mg/kg) administration in mice. The compound was found active in novel object recognition test in mice, at 0.5, 1 and 5 mg/kg. Docking to 5-HT7R homology models indicated a plausible binding mode which explain the unusually high selectivity over the related CNS targets. Halogen bond formation between the most potent derivatives and the receptor is consistent with both the docking results and SAR. 5-Chlorine, bromine and iodine substitution resulted in a 13, 27 and 89-fold increase in binding affinities, respectively, and in enhanced 5-HT1AR selectivity.
Collapse
|
11
|
Norouzi-Javidan A, Javanbakht J, Barati F, Fakhraei N, Mohammadi F, Dehpour AR. Serotonin 5-HT7 receptor agonist, LP-211, exacerbates Na(+), K(+)-ATPase/Mg(2+)-ATPase imbalances in spinal cord-injured male rats. Diagn Pathol 2015; 10:157. [PMID: 26369408 PMCID: PMC4570585 DOI: 10.1186/s13000-015-0397-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/28/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The observed controversy that N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide (LP-211), a selective serotonin (5-HT7) receptor agonist, may either modify or exacerbate imbalances in serum electrolyte concentrations and renal tissue of spinal cord trauma cases has not been reported yet. The aim of this study was to better understand the effects of a new 5-HT7 receptor agonist, LP-211, on serum electrolyte changes in spinal cord injured- (SCI) rats. METHODS Sixty male rats were assigned to the following groups: A) Intact (saline as vehicle, 1 ml/kg, i.p.), B) Intact [LP-211, (0.003-0.3 mg/kg, i.p.)], C) Sham-operated [laminectomy + vehicle (1 ml/kg, i.p.)], D) Sham-operated [laminectomy + LP-211 (0.003-0.3 mg/kg, i.p.)], E) Treatment [laminectomy + spinal trauma (SCI) + vehicle (1 ml/kg, i.p.)], F) Treatment [laminectomy + spinal trauma + LP-211 (0.003-0.3 mg/kg, i.p.)]. SCI was performed by placing an aneurysm clip, extradurally at the level of T10. After two weeks, LP-211 was administered cumulatively and each dose was injected (i.p.) with 20 min interval. At the end of the experiment, blood samples were collected for biochemical evaluations of the electrolytes employing standard commercial kits. RESULTS The present results indicate elevated serum levels of Na(+), K(+), and Mg(2+) in SCI rats and significant differences demonstrated between the groups [P < 0.001, F(5, 35) = 23.92], [P < 0.001, F(5, 35) = 67.63], [P < 0.001, F(5, 35) = 71.144], respectively. So that, in groups B, D and F, there was a significant increase in K(+) and Mg(2+) serum levels compared to the groups A, C, and E (P < 0.001). Furthermore, Na(+) serum levels in SCI (LP-211), laminectomy (LP-211), and intact (LP-211) groups tended to be statistically lower than SCI (saline), laminectomy (saline) and intact (saline) groups. Infact, hyponatremia, hyperkalemia and hypermagnesemia was obtained in group F. Nevertheless, in the remaining measured serum electrolytes such as calcium (Ca(2+)), iron (Fe(2+)) and phosphorus (P(3-)), chlorine (Cl(-)), copper (Cu(+)), and zinc (Zu(+)), no significant changes were observed. CONCLUSION It was shown that acute additive LP-211 treatments in the SCI group led to hyponatremia, hyperkalemia and hypermagnesemia, it may be stated that LP-211 treatment as a promising candidate for treating SCI complications in some systems especially urinary tract might take into consideration and further studies would be needed to clarify its benefits or drawbacks. The observed discrepancies, nevertheless; will also pose new questions. Altogether, this will ultimately contribute to further understanding the pathophysiological role regarding 5-HT7 receptor activation.
Collapse
Affiliation(s)
- Abbas Norouzi-Javidan
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Javad Javanbakht
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Fardin Barati
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Nahid Fakhraei
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Mohammadi
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.
- Experimental Medicine Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran.
| |
Collapse
|
12
|
Watts SW, Darios ES, Seitz BM, Thompson JM. 5-HT is a potent relaxant in rat superior mesenteric veins. Pharmacol Res Perspect 2015; 3:e00103. [PMID: 25692021 PMCID: PMC4317234 DOI: 10.1002/prp2.103] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/02/2014] [Accepted: 09/15/2014] [Indexed: 01/10/2023] Open
Abstract
Serotonin (5-HT, 5-hydroxytryptamine) reduces blood pressure of the conscious rat when administered chronically (1 week). 5-HT does not directly relax isolated arteries, and microsphere experiments in 5-HT-infused rats suggested that 5-HT increased flow to the splanchnic bed. We hypothesized that 5-HT increased splanchnic flow because of direct venous relaxation; our focus was thus on the superior mesenteric vein (SMV) as an important vein in splanchnic circulation. Real-time RT-PCR, immunohistochemistry and Western analyses supported the predominant expression of the 5-HT2B and 5-HT7 receptor in the SMV. The SMV was mounted in tissue baths for measurement of isometric contraction. 5-HT caused a concentration-dependent relaxation of the endothelin-1 (ET-1)-contracted vein. The threshold of 5-HT-induced venous relaxation was significantly lower than for 5-HT-induced venous contraction (∼2 vs. 700 nmol/L, respectively). A series of serotonergic agonists established in their use of receptor characterization was tested, and the following rank order of potency found for agonist-induced relaxation (receptor selectivity): 5-CT (5-HT1/5-HT7)>5-HT = LP-44 (5-HT7)>PNU109291 (5-HT1D) = BW723C86 (5-HT2B). 8-OH-DPAT (5-HT1A/7), CP93129 (5-HT1B), mCPBG (5-HT3/4), AS19 (5-HT7) and TCB-2 (5-HT2A) did not relax the isolated vein. Consistent with these findings, two different 5-HT7 receptor antagonists SB 269970 and LY215840 but not the 5-HT2B receptor antagonist LY272015 nor the nitric oxide synthase inhibitor LNNA abolished 5-CT-induced relaxation of the isolated SMV. 5-CT (1 μg kg−1 min−1, sc) also reduced blood pressure over 7 days. These findings suggest that 5-HT directly relaxes the SMV primarily through activation of the 5-HT7 receptor.
Collapse
Affiliation(s)
- Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University East Lansing, Michigan, 48824
| | - Emma S Darios
- Department of Pharmacology and Toxicology, Michigan State University East Lansing, Michigan, 48824
| | - Bridget M Seitz
- Department of Pharmacology and Toxicology, Michigan State University East Lansing, Michigan, 48824
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University East Lansing, Michigan, 48824
| |
Collapse
|
13
|
Anwar MA, Ford WR, Broadley KJ, Herbert AA. Vasoconstrictor and vasodilator responses to tryptamine of rat-isolated perfused mesentery: comparison with tyramine and β-phenylethylamine. Br J Pharmacol 2012; 165:2191-202. [PMID: 21958009 PMCID: PMC3413856 DOI: 10.1111/j.1476-5381.2011.01706.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Tryptamine increases blood pressure by vasoconstriction, but little is known about its actions on the mesentery, in particular the resistance arteries. Tryptamine interacts with trace amine-associated receptors (TAARs) and because of its structural similarity to 5-HT, it may also interact with 5-HT receptors. Our hypothesis is therefore that the rat mesenteric arterial bed will exhibit vasopressor and vasodepressor responses to tryptamine via both 5-HT and TAARs. EXPERIMENTAL APPROACH Tryptamine-evoked responses were assayed from pressure changes of the rat-isolated mesenteric vasculature perfused at constant flow rate in the absence and presence of adrenoceptor and 5-HT receptor antagonists. KEY RESULTS Tryptamine caused dose-dependent vasoconstriction of the mesenteric arterial bed as increases in perfusion pressure. These were unaffected by the α1-adrenoceptor antagonist, prazosin, but were attenuated by the non-selective α-adrenoceptor antagonist, phentolamine. The 5-HT2A receptor antagonists, ketanserin and ritanserin, abolished the tryptamine-induced pressure increases to reveal vasodilator responses in mesenteric beds preconstricted with phenylephrine. These tryptamine-induced vasodilator responses were unaffected by the 5-HT7 receptor antagonist, SB269970, but were eliminated by the NOS inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME). Tyramine and β-phenylethylamine also caused vasodilatation in pre-constricted vasculature, which was also abolished by L-NAME. CONCLUSIONS AND IMPLICATIONS Tryptamine causes vasoconstriction of the mesenteric vasculature via 5-HT2A receptors, which when inhibited exposed vasorelaxant effects in pre-constricted tissues. The vasodilatation was independent of 5-HT2A and 5-HT7 receptors but like that for tyramine and β-phenylethylamine was due to NO release. Potency orders suggest TAAR involvement in the vasodilatation by these trace amines.
Collapse
Affiliation(s)
- M A Anwar
- Division of Pharmacology, Welsh School of Pharmacy, Cardiff University, Cardiff, UK
| | | | | | | |
Collapse
|
14
|
Johnson MW, Sewell RA, Griffiths RR. Psilocybin dose-dependently causes delayed, transient headaches in healthy volunteers. Drug Alcohol Depend 2012; 123:132-40. [PMID: 22129843 PMCID: PMC3345296 DOI: 10.1016/j.drugalcdep.2011.10.029] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 10/03/2011] [Accepted: 10/31/2011] [Indexed: 12/21/2022]
Abstract
BACKGROUND Psilocybin is a well-characterized classic hallucinogen (psychedelic) with a long history of religious use by indigenous cultures, and nonmedical use in modern societies. Although psilocybin is structurally related to migraine medications, and case studies suggest that psilocybin may be efficacious in treatment of cluster headache, little is known about the relationship between psilocybin and headache. METHODS This double-blind study examined a broad range of psilocybin doses (0, 5, 10, 20, and 30 mg/70 kg) on headache in 18 healthy participants. RESULTS Psilocybin frequently caused headache, the incidence, duration, and severity of which increased in a dose-dependent manner. All headaches had delayed onset, were transient, and lasted no more than a day after psilocybin administration. CONCLUSIONS Possible mechanisms for these observations are discussed, and include induction of delayed headache through nitric oxide release. These data suggest that headache is an adverse event to be expected with the nonmedical use of psilocybin-containing mushrooms as well as the administration of psilocybin in human research. Headaches were neither severe nor disabling, and should not present a barrier to future psilocybin research.
Collapse
Affiliation(s)
- Matthew W Johnson
- Johns Hopkins University School of Medicine, Department of Psychiatry and Behavioral Sciences, Behavioral Biology Research Center, Baltimore, MD 21224-6823, USA.
| | | | | |
Collapse
|
15
|
Kovács A, Hársing LG, Szénási G. Vasoconstrictor 5-HT receptors in the smooth muscle of the rat middle cerebral artery. Eur J Pharmacol 2012; 689:160-4. [PMID: 22659115 DOI: 10.1016/j.ejphar.2012.05.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 05/07/2012] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
Abstract
Serotonin (5-HT) can constrict cerebral arteries via activation of 5-HT(1B) and 5-HT(2A) receptors. Our goal was to reveal the importance and relative contribution of the two 5-HT receptor subtypes to the serotonin-induced vasoconstriction in the rat middle cerebral artery. The vasoconstrictor effects of 5-carboxamidotryptamine, sumatriptan and 5-HT were measured without and with pre-treatment with SB 216641 (5-HT(1B) antagonist), or ritanserin, (5-HT(2A) antagonist), in endothelium-denuded arteries, in vitro. All agonists caused vasoconstrictions. The order of potency (EC(50)) of the compounds was: 5-carboxamidotryptamine (14±3 nM)>5-HT (270±30 nM)>sumatriptan (5.8±1.9 μM). The concentration-response curve of 5-carboxamidotryptamine resembled the sum of two sigmoid curves (EC(50) 14±3 nM and 15±7 μM), and SB 216641 and ritanserin antagonized its low and high concentration components, respectively. Vasoconstrictions evoked by 5-HT at low and high concentrations were also fully antagonized by SB 216641 and ritanserin, respectively. Sumatriptan constricted the middle cerebral artery exclusively via 5-HT(1B) receptors. The efficacy of 5-carboxamidotryptamine and sumatriptan was low in comparison to the maximum contractile force elicited by 120 mmol/l KCl, reaching only 18-23% for 5-HT(1B) and 14% for 5-HT(2A) receptor activation. In conclusion, 5-HT produced small vasoconstrictions in the rat middle cerebral artery that were mediated by 5-HT(1B) receptors with high potency and by 5-HT(2A) receptors with low potency. Thus, 5-HT may have a minor physiological role in blood flow regulation via 5-HT(1B) receptor activation while 5-HT(2A) receptors seem to have a pathophysiological role in this vessel.
Collapse
Affiliation(s)
- Anikó Kovács
- EGIS Pharmaceuticals Plc., Division of Preclinical Research, 1106 Keresztúri út 30-38, Budapest, Hungary
| | | | | |
Collapse
|
16
|
Itoh T, Kajikuri J. Characteristics of the actions by which 5-HT affects electrical and mechanical activities in rabbit jugular vein. Br J Pharmacol 2012; 164:979-91. [PMID: 21449974 DOI: 10.1111/j.1476-5381.2011.01373.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE 5-HT is known to be a potent vasospasmogenic agonist in various arteries. However, in veins the vasomodulating actions of 5-HT, and the underlying mechanisms, remain to be fully clarified. Here, we characterized the actions by which 5-HT affects electrical and mechanical activities in the rabbit jugular vein. EXPERIMENTAL APPROACH Membrane potential and isometric tension were measured in endothelium-intact and -denuded preparations. Localization of 5-HT receptor subtypes was examined immunohistochemically. KEY RESULTS 5-HT induced a transient then a small, sustained smooth muscle cell hyperpolarization in endothelium-intact strips. In endothelium-denuded strips, 5-HT induced only a sustained hyperpolarization, and this was changed to a depolarization by the selective 5-HT(7) receptor inhibitor SB269970. This depolarization was inhibited by the 5-HT(2A) receptor blocker sarpogrelate. 5-HT induced a relaxation of PGF(2α) -induced contracted strips that was similar in endothelium-intact and -denuded preparations. The latter relaxation was changed to contraction by SB269970 and this contraction was inhibited by sarpogrelate. Immunoreactive responses against endothelial and smooth muscle 5-HT(2A) receptors and smooth muscle 5-HT(7) receptors were identified in the vein. The 5-HT-induced relaxation of the PGF(2α) contraction was inhibited by the cAMP-dependent protein kinase inhibitor Rp-cAMPS and by the AC inhibitor SQ22536. CONCLUSIONS AND IMPLICATIONS These results indicate that 5-HT activates both smooth muscle 5-HT(7) receptors (to produce relaxation) and smooth muscle 5-HT(2A) receptors (to produce contraction) in rabbit jugular vein. We suggest that in this particular vein, the 5-HT(2A) receptor-induced depolarization and contraction are masked by the 5-HT(7) receptor-induced responses, possibly via actions mediated by cAMP.
Collapse
Affiliation(s)
- Takeo Itoh
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Japan.
| | | |
Collapse
|
17
|
Watts SW, Morrison SF, Davis RP, Barman SM. Serotonin and blood pressure regulation. Pharmacol Rev 2012; 64:359-88. [PMID: 22407614 DOI: 10.1124/pr.111.004697] [Citation(s) in RCA: 262] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
5-Hydroxytryptamine (5-HT; serotonin) was discovered more than 60 years ago as a substance isolated from blood. The neural effects of 5-HT have been well investigated and understood, thanks in part to the pharmacological tools available to dissect the serotonergic system and the development of the frequently prescribed selective serotonin-reuptake inhibitors. By contrast, our understanding of the role of 5-HT in the control and modification of blood pressure pales in comparison. Here we focus on the role of 5-HT in systemic blood pressure control. This review provides an in-depth study of the function and pharmacology of 5-HT in those tissues that can modify blood pressure (blood, vasculature, heart, adrenal gland, kidney, brain), with a focus on the autonomic nervous system that includes mechanisms of action and pharmacology of 5-HT within each system. We compare the change in blood pressure produced in different species by short- and long-term administration of 5-HT or selective serotonin receptor agonists. To further our understanding of the mechanisms through which 5-HT modifies blood pressure, we also describe the blood pressure effects of commonly used drugs that modify the actions of 5-HT. The pharmacology and physiological actions of 5-HT in modifying blood pressure are important, given its involvement in circulatory shock, orthostatic hypotension, serotonin syndrome and hypertension.
Collapse
Affiliation(s)
- Stephanie W Watts
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA.
| | | | | | | |
Collapse
|
18
|
Matthys A, Haegeman G, Van Craenenbroeck K, Vanhoenacker P. Role of the 5-HT7 receptor in the central nervous system: from current status to future perspectives. Mol Neurobiol 2011; 43:228-53. [PMID: 21424680 DOI: 10.1007/s12035-011-8175-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 03/01/2011] [Indexed: 12/11/2022]
Abstract
Pharmacological and genetic tools targeting the 5-hydroxytryptamine (5-HT)7 receptor in preclinical animal models have implicated this receptor in diverse (patho)physiological processes of the central nervous system (CNS). Some data obtained with 5-HT7 receptor knockout mice, selective antagonists, and, to a lesser extent, agonists, however, are quite contradictory. In this review, we not only discuss in detail the role of the 5-HT7 receptor in the CNS but also propose some hypothetical models, which could explain the observed inconsistencies. These models are based on two novel concepts within the field of G protein-coupled receptors (GPCR), namely biphasic signaling and G protein-independent signaling, which both have been shown to be mediated by GPCR dimerization. This led us to suggest that the 5-HT7 receptor could reside in different dimeric contexts and initiate different signaling pathways, depending on the neuronal circuitry and/or brain region. In conclusion, we highlight GPCR dimerization and G protein-independent signaling as two promising future directions in 5-HT7 receptor research, which ultimately might lead to the development of more efficient dimer- and/or pathway-specific therapeutics.
Collapse
Affiliation(s)
- Anne Matthys
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Department of Physiology, Ghent University (UGent), Ghent, Belgium
| | | | | | | |
Collapse
|
19
|
Leopoldo M, Lacivita E, Berardi F, Perrone R, Hedlund PB. Serotonin 5-HT7 receptor agents: Structure-activity relationships and potential therapeutic applications in central nervous system disorders. Pharmacol Ther 2010; 129:120-48. [PMID: 20923682 DOI: 10.1016/j.pharmthera.2010.08.013] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 08/26/2010] [Indexed: 12/19/2022]
Abstract
Since its discovery in the 1940s in serum, the mammalian intestinal mucosa, and in the central nervous system, serotonin (5-HT) has been shown to be involved in virtually all cognitive and behavioral human functions, and alterations in its neurochemistry have been implicated in the etiology of a plethora of neuropsychiatric disorders. The cloning of 5-HT receptor subtypes has been of importance in enabling them to be classified as specific protein molecules encoded by specific genes. The 5-HT(7) receptor is the most recently classified member of the serotonin receptor family. Since its identification, it has been the subject of intense research efforts driven by its presence in functionally relevant regions of the brain. The availability of some selective antagonists and agonists, in combination with genetically modified mice lacking the 5-HT(7) receptor, has allowed for a better understanding of the pathophysiological role of this receptor. This paper reviews data on localization and pharmacological properties of the 5-HT(7) receptor, and summarizes the results of structure-activity relationship studies aimed at the discovery of selective 5-HT(7) receptor ligands. Additionally, an overview of the potential therapeutic applications of 5-HT(7) receptor agonists and antagonists in central nervous system disorders is presented.
Collapse
Affiliation(s)
- Marcello Leopoldo
- Dipartimento Farmaco-Chimico, Università degli Studi di Bari "A. Moro", via Orabona, 4, 70125 Bari, Italy.
| | | | | | | | | |
Collapse
|
20
|
Leopoldo M, Lacivita E, Berardi F, Perrone R. 5-HT(7) receptor modulators: a medicinal chemistry survey of recent patent literature (2004 - 2009). Expert Opin Ther Pat 2010; 20:739-54. [PMID: 20476847 DOI: 10.1517/13543776.2010.484802] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
IMPORTANCE OF THE FIELD The 5-HT(7) receptors are discretely localized within the CNS (thalamus, hypothalamus, limbic and cortical regions). The 5-HT(7) receptors are also present in smooth muscle cells from blood vessels and have been reported in gastrointestinal tract as well as in rat lumbar dorsal root and sympathetic ganglia. The 5-HT(7) receptors have been implicated in depression, disorders related to circadian rhythms, pain and migraine. Thus, there is a great interest in developing potent and selective 5-HT(7) receptor modulators. AREAS COVERED IN THIS REVIEW This review article highlights the research advances published in the patent literature between January 2004 and December 2009, giving emphasis to the medicinal chemist's standpoint. WHAT THE READER WILL GAIN Readers will rapidly gain an overview of the various 5-HT(7) receptor modulators reported in the patent literature in the past 6 years. Furthermore, the readers will learn which structure type can interact with 5-HT(7) receptor and also the different companies that are the main players in the field. TAKE HOME MESSAGE Although no 5-HT(7) modulator has entered clinical trials, the development and future use of different agonists and antagonists suitable for use in vivo seem very promising.
Collapse
Affiliation(s)
- Marcello Leopoldo
- Dipartimento Farmaco-Chimico, Università degli Studi di Bari A. Moro, via Orabona 4, Bari 70125, Italy.
| | | | | | | |
Collapse
|
21
|
The 5-HT7 receptor and disorders of the nervous system: an overview. Psychopharmacology (Berl) 2009; 206:345-54. [PMID: 19649616 PMCID: PMC2841472 DOI: 10.1007/s00213-009-1626-0] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 07/14/2009] [Indexed: 12/20/2022]
Abstract
RATIONALE The 5-HT(7) receptor is a more recently discovered G-protein-coupled receptor for serotonin. The functions and possible clinical relevance of this receptor are not yet fully understood. OBJECTIVE The present paper reviews to what extent the use of animal models of human psychiatric and neurological disorders have implicated the 5-HT(7) receptor in such disorders. The studies have used a combination of pharmacological and genetic tools targeting the receptor to evaluate effects on behavior. RESULTS Models of anxiety and schizophrenia have yielded mixed results with no clear role for the 5-HT(7) receptor described in these disorders. Some data are available for epilepsy, migraine, and pain but it is still very early to draw any definitive conclusions. There is a considerable amount of evidence supporting a role for the 5-HT(7) receptor in depression. Both blockade and inactivation of the receptor have resulted in an antidepressant-like profile in models of depression. Supporting evidence has also been obtained in sleep studies. Especially interesting are the augmented effects achieved by combining antidepressants and 5-HT(7) receptor antagonists. The antidepressant effect of amisulpride has been shown to most likely be mediated by the 5-HT(7) receptor. CONCLUSIONS The use of pharmacological and genetic tools in preclinical animal models strongly supports a role for the 5-HT(7) receptor in depression. Indirect evidence exists showing that 5-HT(7) receptor antagonism is clinically useful in the treatment of depression. Available data also indicate a possible involvement of the 5-HT(7) receptor in anxiety, epilepsy, pain, and schizophrenia.
Collapse
|
22
|
Figueroa KW, Martin GR, Pulido-Rios MT. 5-Hydroxytryptamine receptor assays. CURRENT PROTOCOLS IN PHARMACOLOGY 2009; Chapter 4:Unit4.19. [PMID: 22294394 DOI: 10.1002/0471141755.ph0419s46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
5-Hydroxytryptamine (5-HT) receptors, by virtue of their broad expression pattern in peripheral and central tissues, regulate diverse physiological and behavioral responses through the activation of fourteen molecularly distinct receptor subtypes. The tissue-specific distribution of these receptors confers specificity for the actions of serotonin and highlights the therapeutic potential of serotonin receptor modulators. To better assess this therapeutic potential, it is useful to characterize serotonergic agonists and antagonists in physiologically relevant organ systems. Provided in this unit are twelve tissue bath assays using vascular and smooth muscle tissues isolated from guinea-pig, rat, and rabbit. These tests make possible the analyses of compounds at nine serotonin receptor subtypes.
Collapse
|
23
|
Boussery K, Lambrecht S, Delaey C, Van de Voorde J. Clozapine Directly Relaxes Bovine Retinal Arteries. Curr Eye Res 2009; 30:139-46. [PMID: 15814472 DOI: 10.1080/02713680490904377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE It was suggested that clozapine might be helpful in the development of new antiglaucoma agents, as it combines lowering the intraocular pressure after topical instillation with vasodilation. This study aimed to evaluate and characterize the vasodilatory effect of clozapine in isolated bovine retinal arteries (BRAs). METHODS Retinal arteries were isolated from bovine eyes and mounted in the organ bath of a small vessel myograph. RESULTS Cumulative addition of clozapine (1 nM to 10 microM) caused a concentration-dependent relaxation of the BRAs. Removal of the endothelium, inhibition of nitric oxide synthase and of soluble guanylyl cyclase reduced the clozapine response, whereas cyclooxygenase inhibition had no influence. A Ca2+ channel activator, a 5-hydroxytryptamine receptor antagonist, and an adenosine receptor antagonist failed in affecting the clozapine-induced relaxations. CONCLUSIONS Clozapine relaxes bovine retinal arteries. Endothelium-derived NO seems to be involved, whereas prostanoids, calcium entry blockade, 5-HT7 receptor stimulation, and adenosine receptor stimulation do not.
Collapse
Affiliation(s)
- Koen Boussery
- Department of Physiology and Pathophysiology, Ghent University, Ghent, Belgium
| | | | | | | |
Collapse
|
24
|
Martínez-García E, García-Iglesias B, Terrón JA. Effect of central serotonin depletion on 5-HT receptor-mediated vasomotor responses in the middle meningeal artery of anaesthetized rats. ACTA ACUST UNITED AC 2009; 29:43-50. [PMID: 19302555 DOI: 10.1111/j.1474-8673.2009.00430.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
1 It has been hypothesized that craniovascular 5-HT receptors mediating dilatation of cranial vessels undergo sensitization on decreased serotonergic transmission in migraine. This study analysed the effect of chemical lesion of the 5-HT system in the brain with 5,7-dihydroxytryptamine (5,7-DHT) on 5-HT receptor-mediated dilator responses to 5-carboxamidotryptamine (5-CT) in the middle meningeal artery of anaesthetized rats. 5-CT has recently been shown to elicit dilator responses in this cranial vessel via 5-HT(7) receptors and, to a much lesser extent, 5-HT(1B/1D) receptors. 2 Pretreatment with 5,7-DHT produced a drastic and selective decrease of 5-HT levels in the brain (78 +/- 6% and 94 +/- 2% in dorsal raphe and hypothalamic paraventricular nuclei, respectively) compared with controls (1% ascorbic acid). 3 Topical application of 5-CT (1-1000 microm) to exposed dura mater encephali produced concentration-dependent decreases in diastolic blood pressure and dilator responses in the middle meningeal artery that were similar in vehicle- and 5,7-DHT-pretreaed animals. 4 Hypotensive and meningeal dilator responses to 5-CT were unaltered by the 5-HT(1B/1D) receptor antagonist, GR-127935 (1 mg kg(-1), i.v.), but were strongly inhibited by the 5-HT(7) receptor antagonist, SB-269970 (1 mg kg(-1), i.v.), with similar efficacy, in both groups of animals. Treatment with GR-127935 + SB-269970 (1 mg kg(-1), i.v. each), produced a stronger inhibitory effect than individual treatments on hypotensive but not on meningeal responses to 5-CT. Meningeal 5-HT(7) receptor-mediated responses (i.e. in GR-127935-pretreated animals) were unchanged by 5,7-DHT pretreatment. 5 Results suggest that the sensitivity of craniovascular 5-HT(7) receptors mediating dilatation is unaffected by a decrease of 5-HT levels in the brain. A neuronal involvement of 5-HT in migraine seems more likely, therefore.
Collapse
Affiliation(s)
- E Martínez-García
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Zacatenco, Mexico D.F., Mexico
| | | | | |
Collapse
|
25
|
Role of monoamine oxidases in the exaggerated 5-hydroxytryptamine-induced tension development of human isolated preeclamptic umbilical artery. Eur J Pharmacol 2009; 605:129-37. [PMID: 19248248 DOI: 10.1016/j.ejphar.2008.12.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigated the role(s) of monoamine oxidases (MAOs) on the altered 5-hydroxytryptamine (5-HT, serotonin)-induced tension development of the isolated umbilical artery of preeclamptic pregnancy of Chinese women. An enhanced 5-HT-induced tension development of the umbilical artery of preeclamptic pregnancy was observed when compared with that of normal pregnancy. The enhanced component of 5-HT-induced tension development was eradicated by clorgyline (a MAO-A inhibitor). Blockade of eNOS (endothelial isoform nitric oxide synthase) (N(omega)-nitro-L-arginine methyl ester), 5-HT transporter (citalopram), 5-HT receptor subtypes (5HT2B, SB 204741; 5-HT2C, RS 102221; 5-HT7, SB 269970), and endothelium denudation of the umbilical artery of normal pregnancy mimicked the enhanced 5-HT-induced tension development as observed in the preeclamptic tissues. In contrast, no apparent changes in 5-HT-induced tension development of the umbilical artery of preeclamptic pregnancy were observed with the same pharmacological manipulations. A decreased protein expression levels of MAO-A and eNOS (no iNOS and MAO-B expression was detected) and no change in caveolin-1 and 5-HT transporter expression were demonstrated in the umbilical artery (endothelium intact) lysate of preeclamptic pregnancy, compared to that of the umbilical artery of normal pregnancy. Thus, in the umbilical artery of preeclamptic pregnancy, a decrease of MAO-A and eNOS protein expression levels are probably associated with, or responsible for, the exaggerated 5-HT-induced tension development.
Collapse
|
26
|
Medina RA, Sallander J, Benhamú B, Porras E, Campillo M, Pardo L, López-Rodríguez ML. Synthesis of new serotonin 5-HT7 receptor ligands. Determinants of 5-HT7/5-HT1A receptor selectivity. J Med Chem 2009; 52:2384-92. [PMID: 19326916 DOI: 10.1021/jm8014553] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis of a new set of compounds of general structure I (1-20) with structural modifications in the pharmacophoric elements of the previously reported lead UCM-5600. The new derivatives have been evaluated for binding affinity at 5-HT(7) and 5-HT(1A) receptors. The influence of the different structural features in terms of 5-HT(7)/5-HT(1A) receptor affinity and selectivity was analyzed by computational simulations of the complexes between compounds I and beta(2)-based 3-D models of these receptors. Compound 18 (HYD(1) = 1,3-dihydro-2H-indol-2-one; spacer = -(CH(2))(4)-; HYD(2) + HYD(3) = 3,4-dihydroisoquinolin-2(1H)-yl) exhibits high 5-HT(7)R affinity (K(i) = 7 nM) and selectivity over the 5-HT(1A)R (31-fold), and has been characterized as a partial agonist of the human 5-HT(7)R.
Collapse
Affiliation(s)
- Rocío A Medina
- Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | | | | | | | | | | | | |
Collapse
|
27
|
Volk B, Barkóczy J, Hegedus E, Udvari S, Gacsályi I, Mezei T, Pallagi K, Kompagne H, Lévay G, Egyed A, Hársing LG, Spedding M, Simig G. (Phenylpiperazinyl-butyl)oxindoles as selective 5-HT7 receptor antagonists. J Med Chem 2008; 51:2522-32. [PMID: 18361484 DOI: 10.1021/jm070279v] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of potent 5-hydroxytryptamine 7 (5-HT 7) ligands has been synthesized that contain a 1,3-dihydro-2 H-indol-2-one (oxindole) skeleton. The binding of these compounds to the 5-HT 7 and 5-HT 1A receptors was measured. Despite the structural similarity of these two serotonin receptor subtypes, several derivatives exhibited a high selectivity to the 5-HT 7 receptor. According to the structure-activity relationship observations, compounds unsubstituted at the oxindole nitrogen atom and containing a tetramethylene spacer between the oxindole skeleton and the basic nitrogen atom are the most potent ligands. Concerning the basic group, besides the moieties of the 4-phenylpiperazine type, halophenyl-1,2,3,6-tetrahydropyridines also proved to be 5-HT 7 receptor-ligands. Because of halogen substitution on the aromatic rings, good metabolic stability could be achieved. A representative of the family, 3-{4-[4-(4-chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-6-fluoro-1,3-dihydro-2 H-indol-2-one ( 9e') exhibited selective 5-HT 7 antagonist activity ( K i = 0.79 nM). The in vivo pharmacological potencies of these 5-HT 7 receptor-ligands were estimated by the conflict drinking (Vogel) and the light-dark anxiolytic tests.
Collapse
Affiliation(s)
- Balázs Volk
- Chemical Research Division and Preclinical Research Division, EGIS Pharmaceuticals Plc, P.O. Box 100, H-1475 Budapest, Hungary.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Recent Advances on the 5-HT5A, 5-HT6 and 5-HT7 Receptors. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2008. [DOI: 10.1016/s0065-7743(08)00002-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
|
29
|
Cairrão E, Álvarez E, Santos-Silva AJ, Verde I. Potassium channels are involved in testosterone-induced vasorelaxation of human umbilical artery. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:375-83. [DOI: 10.1007/s00210-007-0213-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 10/28/2007] [Indexed: 10/22/2022]
|
30
|
Johnson MP, Fernandez F, Colson NJ, Griffiths LR. A pharmacogenomic evaluation of migraine therapy. Expert Opin Pharmacother 2007; 8:1821-35. [PMID: 17696786 DOI: 10.1517/14656566.8.12.1821] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Migraine is a common idiopathic primary headache disorder with significant mental, physical and social health implications. Accompanying an intense unilateral pulsating head pain other characteristic migraine symptoms include nausea, emesis, phonophobia, photophobia and in approximately 20-30% of migraine cases, neurologic disturbances associated with the aura phase. Although selective serotonin (5-HT) receptor agonists (i.e., 5-HT(1B/1D)) are successful in alleviating migrainous symptoms in < or = 70% of known sufferers, for the remaining 30%, additional migraine abortive medications remain unsuccessful, not tested or yet to be identified. Genetic characterization of the migrainous disorder is making steady progress with an increasing number of genomic susceptibility loci now identified on chromosomes 1q, 4q, 5q, 6p, 11q, 14q, 15q, 17p, 18q, 19p and Xq. The 4q, 5q, 17p and 18q loci involve endophenotypic susceptibility regions for various migrainous symptoms. In an effort to develop individualized pharmacotherapeutics, the identification of these migraine endophenotypic loci may well be the catalyst needed to aid in this goal. In this review the authors discuss the present treatment of migraine, known genomic susceptibility regions and results from migraine (genetic) association studies. The authors also discuss pharmacogenomic considerations for more individualized migraine prophylactic treatments.
Collapse
Affiliation(s)
- Matthew P Johnson
- Griffith University, Genomics Research Centre, School of Medical Science, PMB 50 GCMC Gold Coast, Queensland, Australia
| | | | | | | |
Collapse
|
31
|
Rauly-Lestienne I, Boutet-Robinet E, Ailhaud MC, Newman-Tancredi A, Cussac D. Differential profile of typical, atypical and third generation antipsychotics at human 5-HT7a receptors coupled to adenylyl cyclase: detection of agonist and inverse agonist properties. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:93-105. [PMID: 17786406 DOI: 10.1007/s00210-007-0182-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 07/29/2007] [Indexed: 11/24/2022]
Abstract
5-HT(7) receptors are present in thalamus and limbic structures, and a possible role of these receptors in the pathology of schizophrenia has been evoked. In this study, we examined binding affinity and agonist/antagonist/inverse agonist properties at these receptors of a large series of antipsychotics, i.e., typical, atypical, and third generation compounds preferentially targeting D(2) and 5-HT(1A) sites. Adenylyl cyclase (AC) activity was measured in HEK293 cells stably expressing the human (h) 5-HT(7a) receptor isoform. 5-HT and 5-CT increased cyclic adenosine monophosphate level by about 20-fold whereas (+)-8-OH-DPAT, the antidyskinetic agent sarizotan, and the novel antipsychotic compound bifeprunox exhibited partial agonist properties at h5-HT(7a) receptors stimulating AC. Other compounds antagonized 5-HT-induced AC activity with pK (B) values which correlated with their pK (i) as determined by competition binding vs [(3)H]5-CT. The selective 5-HT(7) receptor ligand, SB269970, was the most potent antagonist. For antipsychotic compounds, the following rank order of antagonism potency (pK (B)) was ziprasidone > tiospirone > SSR181507 > or = clozapine > or = olanzapine > SLV-314 > SLV-313 > or = aripiprazole > or = chlorpromazine > nemonapride > haloperidol. Interestingly, pretreatment of HEK293-h5-HT(7a) cells with forskolin enhanced basal AC activity and revealed inverse agonist properties for both typical and atypical antipsychotics as well as for aripiprazole. In contrast, other novel antipsychotics exhibited diverse 5-HT(7a) properties; SLV-313 and SLV-314 behaved as quasi-neutral antagonists, SSR181507 acted as an inverse agonist, and bifeprunox as a partial agonist, as mentioned above. In conclusion, the differential properties of third generation antipsychotics at 5-HT(7) receptors may influence their antipsychotic profile.
Collapse
Affiliation(s)
- Isabelle Rauly-Lestienne
- Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 17 avenue Jean Moulin, 81106 Castres Cedex, France
| | | | | | | | | |
Collapse
|
32
|
Callera G, Tostes R, Savoia C, Muscara MN, Touyz RM. Vasoactive peptides in cardiovascular (patho)physiology. Expert Rev Cardiovasc Ther 2007; 5:531-52. [PMID: 17489676 DOI: 10.1586/14779072.5.3.531] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Numerous vasoactive agents play an important physiological role in regulating vascular tone, reactivity and structure. In pathological conditions, alterations in the regulation of vasoactive peptides result in endothelial dysfunction, vascular remodeling and vascular inflammation, which are important processes underlying vascular damage in cardiovascular disease. Among the many vasoactive agents implicated in vascular (patho)biology, angiotensin II (Ang II), endothelin (ET), serotonin and natriuretic peptides appear to be particularly important because of their many pleiotropic actions and because they have been identified as potential therapeutic targets in cardiovascular disease. Ang II, ET-1, serotonin and natriuretic peptides mediate effects via specific receptors, which belong to the group of G-protein-coupled receptors. ET, serotonin and Ang II are primarily vasoconstrictors with growth-promoting actions, whereas natriuretic peptides, specifically atrial, brain and C-type natriuretic peptides, are vasodilators with natriuretic effects. Inhibition of vasoconstrictor actions with drugs that block peptide receptors, compounds that inhibit enzymes that generate vasoactive peptides or agents that increase levels of natriuretic peptides are potentially valuable therapeutic tools in the management of cardiovascular diseases. This review focuses on ET, natriuretic peptides and serotonin. The properties and distribution of these vasoactive agents and their receptors, mechanisms of action and implications in cardiovascular (patho)physiology will be discussed.
Collapse
Affiliation(s)
- Glaucia Callera
- University of Ottawa/Ottawa Health Research Institute, Kidney Research Centre, Ottawa, ON, Canada
| | | | | | | | | |
Collapse
|
33
|
Terrón JA, Martínez-García E. 5-HT7 receptor-mediated dilatation in the middle meningeal artery of anesthetized rats. Eur J Pharmacol 2007; 560:56-60. [PMID: 17316605 PMCID: PMC1832110 DOI: 10.1016/j.ejphar.2007.01.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 12/14/2006] [Accepted: 01/05/2007] [Indexed: 11/22/2022]
Abstract
Topical administration of 5-carboxamidotryptamine (5-CT; 0.01-1000 microM) to the exposed dura mater encephali of anesthetized rats produced decreases in blood pressure and dilatation in the middle meningeal artery. Pretreatment with the 5-HT(1B/1D) receptor antagonist, N-[4-methoxy-3-(4-methyl-1-piperazinyl) phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl) [1,1-biphenyl]-4-carboxamide hydrochloride monohydrate (GR-127935; 1 mg/kg, i.v.), unmasked meningeal dilator responses to lower concentrations of 5-CT, and attenuated those to higher concentrations; GR-127935 also inhibited 5-CT-induced hypotension. The 5-HT7 receptor antagonist, (R)-1-{(3-hydroxyphenyl)sulfonyl}-2-{2-(2-(4-methyl-1-piperidinyl) ethyl} pyrrolidine (SB-269970; 1 mg/kg, i.v.), strongly inhibited dilator and hypotensive responses to 5-CT; the combination of GR-127935+SB-269970 (1 mg/kg, i.v., each) further inhibited meningeal and hypotensive responses. Thus, 5-CT may produce dilatation in the middle meningeal artery via 5-HT7 receptors; complex effects appear to involve 5-HT(1B/1D) receptors.
Collapse
Affiliation(s)
- José A Terrón
- Sección Externa de Farmacología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apdo. Postal 14-740, Zacatenco 07000, México D.F., Mexico.
| | | |
Collapse
|
34
|
Kołaczkowski M, Nowak M, Pawłowski M, Bojarski AJ. Receptor-based pharmacophores for serotonin 5-HT7R antagonists-implications to selectivity. J Med Chem 2007; 49:6732-41. [PMID: 17154504 DOI: 10.1021/jm060300c] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A set of 31 diversified 5-HT7 receptor antagonists was automatically docked to a conformational ensemble of rhodopsin-based 5-HT7R models (flexible docking). It was found that ergolines, aporphines, and tricyclic psychotropic agents were always docked in a pocket formed by TMHs 4-6, and besides the main ionic bond with Asp3.32, they had specific interactions with Phe6.52, Phe6.51, Trp6.48, and Ser5.42. The arylpiperidine, arylpiperazine, or beta-carboline fragment of the complex ligands occupied the same pocket, whereas the terminal amide/imide part of those compounds reached the second cavity formed by TMHs 7-3 and interacted with Phe3.28, Arg7.36, and Tyr7.43. A similar orientation of selective antagonists of the group of arylsulfonamidoalkylamines was observed, that is, the sulfonamide part was located in the second pocket. Coherent docking results allowed the generation of two receptor-based pharmacophores: first containing features necessary for high 5-HT7R affinity and the other defining selectivity for this receptor subtype. The latter model indicated the importance of specific interactions with the residues of the TMHs 7-3 pocket (especially nonconserved Arg7.36) for selectivity over other monoamine GPCRs.
Collapse
Affiliation(s)
- Marcin Kołaczkowski
- Department of Medicinal Chemistry, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | | | | | | |
Collapse
|
35
|
Smith C, Rahman T, Toohey N, Mazurkiewicz J, Herrick-Davis K, Teitler M. Risperidone irreversibly binds to and inactivates the h5-HT7 serotonin receptor. Mol Pharmacol 2006; 70:1264-70. [PMID: 16870886 DOI: 10.1124/mol.106.024612] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Risperidone displays a novel mechanism of antagonism of the h5-HT7 receptor. Pretreatment of the cells with 5 or 20 nM risperidone, followed by removal of the drug from the media, renders the 5-HT7 receptors unresponsive to 10 microM 5-HT for at least 24 h. Thus, risperidone seems to be producing a rapid, long-lasting inactivation of the h5-HT7 receptor. Whole-cell radioligand binding studies indicate that risperidone interacts in an irreversible or pseudo-irreversible manner with the h5-HT7 receptor, thus producing the inactivation. Internalization of the h5-HT7 receptor was not detected by monitoring green fluorescent protein-labeled fluorescent forms of the h5-HT7 receptor exposed to 20 nM risperidone. Ten other antagonists were tested for h5-HT7-inactivating properties, and only 9-OH-risperidone and methiothepin were found to demonstrate the same anomalous properties as risperidone. These results indicate that the h5-HT7 receptor may possess unique structural features that allow certain drugs to induce a conformation resulting in an irreversible interaction in the intact membrane environment. This may indicate that the h5-HT7 receptor is part of a subfamily of G-protein-coupled receptors (GPCRs) possessing this property or that many GPCRs have the potential to be irreversibly blocked, but only select drugs can induce this effect. At the very least, the possibility that highly prescribed drugs, such as risperidone, are irreversibly antagonizing GPCR function in vivo is noteworthy.
Collapse
Affiliation(s)
- Carol Smith
- A-136, Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | | | | | | | | | | |
Collapse
|
36
|
Terrón JA. 2-(2-aminoethyl)-quinoline (D-1997): A Novel Agonist at Craniovascular 5-HT1 Receptors Relevant to Migraine Therapy. CNS DRUG REVIEWS 2006. [DOI: 10.1111/j.1527-3458.2000.tb00152.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
37
|
Janssen P, Prins NH, Moreaux B, Meulemans AL, Lefebvre RA. Characterization of 5-HT7-receptor-mediated gastric relaxation in conscious dogs. Am J Physiol Gastrointest Liver Physiol 2005; 289:G108-15. [PMID: 15746214 DOI: 10.1152/ajpgi.00012.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We aimed to evaluate the gastric relaxant capacity of the 5-HT(1/7)-receptor agonist 5-carboxamidotryptamine (5-CT) in conscious dogs and to clarify the mechanism of action by use of selective antagonists, vagotomy, and in vitro experiments. A barostat enabled us to monitor the intragastric volume in response to different treatments (intravenously administered) before and after supradiaphragmatic vagotomy [results presented as the maximum volume change after treatment (mean; n = 5-11)]. In vitro experiments were performed with isolated muscle strips cut from four different stomach regions of the vagotomized dogs [results were fitted to the operational model of agonism to determine the efficacy parameter tau (n = 5)]. 5-CT (0.5-10 microg/kg) caused a dose-dependent gastric relaxation (29-267 ml) that was completely blocked by the selective 5-HT(7)-receptor antagonist SB-269970 (50 microg/kg). After vagotomy, the relaxation to 10 microg/kg 5-CT was significantly less pronounced (73 vs. 267 ml; P < 0.05) but still blocked by SB-269970, whereas the response to the nitric oxide donor nitroprusside was similar to that before vagotomy (178 vs. 218 ml). In vitro, 5-CT concentration dependently inhibited the PGF(2alpha)-contracted muscle strips before and after vagotomy. Although before and after vagotomy the response in every region was mediated by 5-HT(7) receptors (apparent affinity dissociation constant: SB-269970, 8.2-8.6 vs. 8.3-8.6, respectively), the response after vagotomy was less efficacious (log tau: 1.9 to 0.5 vs. 1.4 to -0.1). The results indicate that the 5-CT-induced proximal stomach relaxation in conscious dogs before and after vagotomy is mediated via 5-HT(7) receptors. The decreased efficacy of 5-CT in vitro after vagotomy is probably related to vagotomy-induced changes in receptor density or coupling efficiency and provides a possible explanation for the decreased in vivo response to 5-CT after vagotomy.
Collapse
Affiliation(s)
- Pieter Janssen
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium.
| | | | | | | | | |
Collapse
|
38
|
Zajdel P, Subra G, Bojarski AJ, Duszyńska B, Pawłowski M, Martinez J. Parallel solid-phase synthesis and characterization of new sulfonamide and carboxamide proline derivatives as potential CNS agents. Bioorg Med Chem 2005; 13:3029-35. [PMID: 15781412 DOI: 10.1016/j.bmc.2005.01.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 01/24/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
A solid-phase synthesis of the 64-member library of novel sulfonamide and carboxamide proline derivatives, focused on the 5-HT7 receptor antagonist SB-258741, was described. The final compounds were obtained in good yields and high purity upon cleavage from SynPhase Lanterns, functionalized by a BAL linker. The library representatives were screened for 5-HT7, 5-HT1A and D2 receptors to explore the impact of a tertiary amine moiety, the length of an alkylene spacer and the aryl fragment on the receptor affinity. The preliminary biological results provided data for further investigation aimed at a search for 5-HT7 receptor agents, and permitted the identification of several compounds with significant 5-HT1A receptor affinity.
Collapse
Affiliation(s)
- Paweł Zajdel
- Laboratoire des Aminoacides, Peptides et Protéines (LAPP), UMR 5810, Faculté de Pharmacie, Université Montpellier I et II, 15 avenue Charles Flahault, 34060 Montpellier, France.
| | | | | | | | | | | |
Collapse
|
39
|
Slassi A, Isaac M, Xin T. Recent progress in 5-HT7receptors: potential treatment of central and peripheral nervous system diseases. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.14.7.1009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
40
|
Denhart DJ, Purandare AV, Catt JD, King HD, Gao A, Deskus JA, Poss MA, Stark AD, Torrente JR, Johnson G, Mattson RJ. Diaminopyrimidine and diaminopyridine 5-HT7 ligands. Bioorg Med Chem Lett 2005; 14:4249-52. [PMID: 15261280 DOI: 10.1016/j.bmcl.2004.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Accepted: 06/03/2004] [Indexed: 10/26/2022]
Abstract
The present studies have identified a series of diaminopyrimidines and diaminopyridines as novel 5-HT(7) receptor ligands. Three regiosiomeric classes of pyrimidines and four regioisomeric classes of pyridines were synthesized and analyzed for binding to the 5-HT(7) receptor. The 5-HT(7) binding affinities of different regioisomers show clearly the structure-activity relationship with position of ring nitrogens.
Collapse
Affiliation(s)
- Derek J Denhart
- Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, CT 06492-7660, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Mattson RJ, Denhart DJ, Catt JD, Dee MF, Deskus JA, Ditta JL, Epperson J, Dalton King H, Gao A, Poss MA, Purandare A, Tortolani D, Zhao Y, Yang H, Yeola S, Palmer J, Torrente J, Stark A, Johnson G. Aminotriazine 5-HT7 antagonists. Bioorg Med Chem Lett 2005; 14:4245-8. [PMID: 15261279 DOI: 10.1016/j.bmcl.2004.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Accepted: 06/03/2004] [Indexed: 10/26/2022]
Abstract
The present studies have identified a series of aminotriazines as novel 5-HT(7) receptor antagonists. Compounds 10 and 17 have high affinity for the 5-HT(7) receptor and do not bind to either the 5-HT(2C) or 5-HT(6) receptors. These compounds produce no agonist effects by themselves, and shift the dose-response curve of 5-CT to the right in the manner of an antagonist.
Collapse
Affiliation(s)
- Ronald J Mattson
- Bristol-Myers Squibb Pharmaceutical Research Institute, 5 Research Parkway, Wallingford, CT 06492-7660, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Jähnichen S, Glusa E, Pertz HH. Evidence for 5-HT2B and 5-HT7 receptor-mediated relaxation in pulmonary arteries of weaned pigs. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2004; 371:89-98. [PMID: 15726452 DOI: 10.1007/s00210-004-1006-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Accepted: 11/11/2004] [Indexed: 11/25/2022]
Abstract
This study characterizes the relaxant response to 5-hydroxytryptamine (5-HT) in prostaglandin F(2alpha) (PGF(2alpha))-precontracted pulmonary arteries of weaned pigs. In arterial rings with intact endothelium, the relaxation to 5-HT was biphasic. The high affinity component of relaxation to 5-HT (0.1-10 nM) was abolished by mechanical removal of the endothelium or after the addition of L: -NAME (200 microM), and was inhibited by the 5-HT(2B/2C) receptor antagonist SB 206553 (1 microM), but not the 5-HT(2C) receptor antagonist SB 242084 (0.1 microM). Endothelium-intact arteries were also relaxed by the selective 5-HT(2B) receptor agonist BW 723C86 (pD(2) 7.7). The relaxant response to BW 723C86 was inhibited by 1 microM SB 206553 (pK(B) 6.8). The low affinity component of relaxation to 5-HT (>/=30 nM) remained unaffected after mechanical removal of the endothelium or the addition of L: -NAME. In endothelium-denuded arterial rings, 5-HT, 5-carboxamidotryptamine (5-CT), 5-methoxytryptamine (5-MeOT), and frovatriptan produced monophasic relaxations with pD(2) values of 6.5, 7.5, 5.9, and 4.7 respectively. Relaxant responses to the agonists were antagonized by the selective 5-HT(7) receptor antagonist SB 269970 (pK(B) 8.2-8.9). The relaxant response to the potent 5-HT(7) receptor agonist 5-CT was also antagonized by methiothepin (pK(B) 9.6), pimozide (pK(B) 8.2), mesulergine (pK(B) 7.7), methysergide (pK(B) 7.4), clozapine (pK(B) 7.6), and spiperone (pK(B) 7.4). The estimated pK(B) values argue in favor of an involvement of 5-HT(7) receptors in the direct vasorelaxant action of 5-HT in the pulmonary arteries of weaned pigs. The relaxant response to 5-CT was associated with an increase in cAMP that was surmountably antagonized by SB 269970 (pK(B) 8.6). The present in vitro bioassay can be used to characterize new drugs with potential agonist or antagonist properties at functional 5-HT(7) receptors.
Collapse
MESH Headings
- Algorithms
- Animals
- Cyclic AMP/physiology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- In Vitro Techniques
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Pulmonary Artery/drug effects
- Pulmonary Artery/physiology
- Radioligand Assay
- Receptor, Serotonin, 5-HT2B/drug effects
- Receptor, Serotonin, 5-HT2B/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Swine
Collapse
Affiliation(s)
- S Jähnichen
- Institut für Pharmazie, Freie Universität Berlin, Königin-Luise-Strasse 2+4, 14195 Berlin (Dahlem), Germany
| | | | | |
Collapse
|
43
|
Hedlund PB, Kelly L, Mazur C, Lovenberg T, Sutcliffe JG, Bonaventure P. 8-OH-DPAT acts on both 5-HT1A and 5-HT7 receptors to induce hypothermia in rodents. Eur J Pharmacol 2004; 487:125-32. [PMID: 15033384 DOI: 10.1016/j.ejphar.2004.01.031] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2003] [Revised: 01/21/2004] [Accepted: 01/28/2004] [Indexed: 10/26/2022]
Abstract
Studies using selective drugs and knockout mice have demonstrated that the 5-HT(7) receptor plays an instrumental role in serotonin-induced hypothermia. There is also evidence supporting an involvement of the 5-HT(1A) receptor, although mainly from studies using 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT(1A/7) receptor agonist. Here we studied the effects of 8-OH-DPAT and selective antagonists for the 5-HT(1A) and 5-HT(7) receptors on body temperature in rats, wild-type (5-HT(7)(+/+)) mice and knockout (5-HT(7)(-/-)) mice. At lower doses (0.3-0.6 mg/kg, i.p.), 8-OH-DPAT decreased body temperature in 5-HT(7)(+/+) mice but not in 5-HT(7)(-/-) mice. At a higher dose (1 mg/kg, i.p.) 8-OH-DPAT induced hypothermia in both 5-HT(7)(-/-) and 5-HT(7)(+/+) mice. The 5-HT(1A) receptor antagonist (S)-N-tert-butyl-3-(4-(2-methoxyphenyl)piperazine-1-yl)-2-phenylpropanamide (WAY-100135) (10 mg/kg, i.p.) inhibited the effect of 8-OH-DPAT at all doses in rats and mice. In 5-HT(7)(+/+) mice the selective 5-HT(7) receptor antagonist (R)-3-(2-(2-(4-methylpiperidin-1-yl)-ethyl)pyrrolidine-1-sulfonyl)phenol (SB-269970) (10 mg/kg, i.p.) fully inhibited the hypothermia induced by 0.3 mg/kg 8-OH-DPAT, but not that of higher doses. In rats, SB-269970 caused a 60% inhibition of the hypothermia induced by 0.3 mg/kg 8-OH-DPAT. Thus, both 5-HT(7) and 5-HT(1A) receptors are involved in a complex manner in thermoregulation, with the 5-HT(7) receptor being more important at lower, possibly more physiological, concentrations.
Collapse
Affiliation(s)
- Peter B Hedlund
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | | | | | | |
Collapse
|
44
|
Nagatomo T, Rashid M, Abul Muntasir H, Komiyama T. Functions of 5-HT2A receptor and its antagonists in the cardiovascular system. Pharmacol Ther 2004; 104:59-81. [PMID: 15500909 DOI: 10.1016/j.pharmthera.2004.08.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The serotonin (5-hydroxytryptamine, 5-HT) receptors have conventionally been divided into seven subfamilies, most of which have several subtypes. Among them, 5-HT(2A) receptor is associated with the contraction of vascular smooth muscle, platelet aggregation and thrombus formation and coronary artery spasms. Accordingly, selective 5-HT(2A) antagonists may have potential in the treatment of cardiovascular diseases. Sarpogrelate, a selective 5-HT(2A) antagonist, has been introduced clinically as a therapeutic agent for the treatment of ischemic diseases associated with thrombosis. Molecular modeling studies also suggest that sarpogrelate is a 5-HT(2A) selective antagonist and is likely to have pharmacological effects beneficial in the treatment of cardiovascular diseases. This review describes the above findings as well as the signaling linkages of the 5-HT(2A) receptors and the mode of agonist binding to 5-HT(2A) receptor using data derived from molecular modeling and site-directed mutagenesis.
Collapse
Affiliation(s)
- Takafumi Nagatomo
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 5-13-2 Kamishinei-cho, Niigata 950-2081, Japan.
| | | | | | | |
Collapse
|
45
|
Holmberg P, Sohn D, Leideborg R, Caldirola P, Zlatoidsky P, Hanson S, Mohell N, Rosqvist S, Nordvall G, Johansson AM, Johansson R. Novel 2-aminotetralin and 3-aminochroman derivatives as selective serotonin 5-HT7 receptor agonists and antagonists. J Med Chem 2004; 47:3927-30. [PMID: 15267230 DOI: 10.1021/jm0498102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The understanding of the physiological role of the G-protein coupled serotonin 5-HT(7) receptor is largely rudimentary. Therefore, selective and potent pharmacological tools will add to the understanding of serotonergic effects mediated through this receptor. In this report, we describe two compound classes, chromans and tetralins, encompassing compounds with nanomolar affinity for the 5-HT(7) receptor and with good selectivity. Within theses classes, we have discovered both agonists and antagonists that can be used for further understanding of the pharmacology of the 5-HT(7) receptor.
Collapse
Affiliation(s)
- Pär Holmberg
- Organic Pharmaceutical Chemistry, Uppsala University, Uppsala Biomedical Centre, Box 574, SE-751 23 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
O'Donohue HA, Abel PW, Bockman CS. Pharmacological properties of serotonin receptor subtypes mediating contraction of bovine inferior alveolar arteries. Arch Oral Biol 2004; 49:223-32. [PMID: 14725814 DOI: 10.1016/j.archoralbio.2003.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To characterise the 5-hydroxytryptamine (5-HT) receptor subtypes mediating contraction of the inferior alveolar artery. Additionally, to determine the role of cyclooxygenase products, nitric oxide, endothelium, monoamine oxidase and 5-HT uptake in modulating contraction of inferior alveolar arteries to 5-HT. METHODS Contractile responses to 5-HT were examined in vitro using ring segments of bovine inferior alveolar arteries. Affinity constants (K(B)'s) of subtype-selective 5-HT receptor antagonists were determined to characterise the 5-HT receptor-subtypes causing contraction of inferior alveolar arteries. RESULTS In 100 nM ketanserin or 30 nM spiperone, 5-HT caused a biphasic contraction best-fit by a two-site curve model, where one site was antagonist-sensitive and the other site antagonist-insensitive. 5-HT(2A) receptor-subtype selective antagonists, ketanserin and spiperone, blocked 5-HT induced contraction with K(B)'s of 1.0 and 0.16 nM, respectively. RS102221 (5-HT(2C) selective) and (S)-WAY100135 (5-HT(1A) selective) blocked 5-HT stimulated contraction with low affinities (K(B)'s=100 nM and 330 nM, respectively). GR55562, a 5-HT(1) receptor subtype antagonist with a reported affinity of 500 nM at the 5-HT(1D) receptor subtype, blocked 5-HT induced contraction with a K(B) of 470 nM. Cylooxygenase inhibition with 50 microM ibuprofen caused a 44% increase in maximal contraction to 5-HT; whereas, nitric oxide inhibition with N(G)-nitro-L-arginine, endothelium removal or inhibition of 5-HT uptake and monoamine oxidase with imipramine and iproniazid, respectively, did not affect 5-HT contraction. CONCLUSIONS Both 5-HT(2A) and 5-HT(1D/1B) receptor subtypes mediate 5-HT induced contraction of the bovine inferior alveolar artery. 5-HT stimulated contraction of the inferior alveolar artery is modulated by a vasodilator prostaglandin.
Collapse
Affiliation(s)
- H A O'Donohue
- Department of Pharmacology, Creighton University School of Medicine, Criss III, Room 553, 2500 California Plaza, Omaha, NE 68178, USA
| | | | | |
Collapse
|
47
|
López-Rodríguez ML, Porras E, Morcillo MJ, Benhamú B, Soto LJ, Lavandera JL, Ramos JA, Olivella M, Campillo M, Pardo L. Optimization of the pharmacophore model for 5-HT7R antagonism. Design and synthesis of new naphtholactam and naphthosultam derivatives. J Med Chem 2004; 46:5638-50. [PMID: 14667218 DOI: 10.1021/jm030841r] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present in this study an optimization of a preliminary pharmacophore model for 5-HT(7)R antagonism, with the incorporation of recently reported ligands and using an efficient procedure with the CATALYST program. The model consists of five features: a positive ionizable atom (PI), a H-bonding acceptor group (HBA), and three hydrophobic regions (HYD). This model has been supported by the design, synthesis, and biological evaluation of new naphtholactam and naphthosultam derivatives of general structure I (39-72). A systematic structure-affinity relationship (SAFIR) study on these analogues has allowed us to confirm that the model incorporates the essential structural features for 5-HT(7)R antagonism. In addition, computational simulation of the complex between compound 56 and a rhodopsin-based 3D model of the 5-HT(7)R transmembrane domain has permitted us to define the molecular details of the ligand-receptor interaction and gives additional support to the proposed pharmacophore model for 5-HT(7)R antagonism: (i) the HBA feature of the pharmacophore model binds Ser(5.42) and Thr(5.43), (ii) the HYD1 feature interacts with Phe(6.52), (iii) the PI feature forms an ionic interaction with Asp(3.32), and (iv) the HYD3 (AR) feature interacts with a set of aromatic residues (Phe(3.28), Tyr(7.43)). These results provide the tools for the design and synthesis of new ligands with predetermined affinities and pharmacological properties.
Collapse
Affiliation(s)
- María L López-Rodríguez
- Departamento de Química Orgánica I, Facultad de Ciencias Químicas, and Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense, E-28040 Madrid, Spain.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Vermeulen ES, Schmidt AW, Sprouse JS, Wikström HV, Grol CJ. Characterization of the 5-HT(7) receptor. Determination of the pharmacophore for 5-HT(7) receptor agonism and CoMFA-based modeling of the agonist binding site. J Med Chem 2004; 46:5365-74. [PMID: 14640545 DOI: 10.1021/jm030826m] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
On the basis of a set of 20 diverse 5-HT(7) receptor agonists, the pharmacophore for 5-HT(7) receptor agonism was determined. Additionally two CoMFA models were developed, based on different alignments of the agonists. Both models show good correlations between experimental and predictive pK(i) values and show a high degree of similarity. The CoMFA fields were subsequently used to map the agonist binding site of the model of the 5-HT(7) receptor. Important roles in ligand binding are attributed to Asp162 of TM3 (interaction with a protonated nitrogen), and Thr244 of TM5 (interaction with a substituent at an aromatic moiety). Amino acid residues of the aromatic cluster of TM6 are hypothesized to play an important role in ligand binding as pi-pi stacking moieties. Agonists missing a hydrogen-bond-accepting moiety, but possessing an aromatic substituent instead, seem to bind the receptor with high affinity as well by occupying a lipophilic pocket hosted by residues of TM5 and TM6.
Collapse
Affiliation(s)
- Erik S Vermeulen
- Department of Medicinal Chemistry, Center for Pharmacy, State University of Groningen, A Deusinglaan 1, NL-9713 AV Groningen, The Netherlands.
| | | | | | | | | |
Collapse
|
49
|
Abstract
Subarachnoid haemorrhage (SAH), occurring with a delay of 4-10 days is linked to cerebral vasospasm (CVS), a pathological constriction of the cerebral arteries. Several agents have been suggested as being responsible - amongst these perhaps 5-hydroxytryptamine (5-HT) and endothelin-1 (ET-1) are the most prominent, given their ability to elicit powerful constriction of arteries. Investigating both 5-HT and ET receptors we observed distinct changes in the receptor phenotype after experimental SAH - namely upregulation of the ETB and 5-HT1B receptors - linked to a higher sensitivity to the endogenous agonists. This multiple receptor upregulation may explain the failure in treating CVS using single receptor antagonists, and may also significantly change our understanding of the effector mechanism behind CVS. So far only the ET and 5-HT receptors have been studied in this regard, but other receptor systems may also undergo changes.
Collapse
|
50
|
Affiliation(s)
- Richard A Glennon
- Department of Medicinal Chemistry, School of Pharmacy, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298-0540, USA.
| |
Collapse
|