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Neural response differences in the rat primary auditory cortex under anesthesia with ketamine versus the mixture of medetomidine, midazolam and butorphanol. Hear Res 2016; 339:69-79. [DOI: 10.1016/j.heares.2016.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/08/2016] [Accepted: 06/15/2016] [Indexed: 11/18/2022]
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So EC, Wu KC, Kao FC, Wu SN. Effects of midazolam on ion currents and membrane potential in differentiated motor neuron-like NSC-34 and NG108-15 cells. Eur J Pharmacol 2013; 724:152-60. [PMID: 24374009 DOI: 10.1016/j.ejphar.2013.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 11/22/2013] [Accepted: 12/16/2013] [Indexed: 11/25/2022]
Abstract
Midazolam (MDL) was known to act through stimulation of benzodiazepine receptors (GABA). Whether midazolam affects ion currents and membrane potential in neurons remains largely unclear. Electrophysiological studies of midazolam actions were performed in differentiated motor neuron-like (NSC-34 and NG108-15) cells. Midazolam suppressed the amplitude of delayed rectifier K(+) current (IK(DR)) in a time- and concentration-dependent manner with an IC50 value of 10.4 µM. Addition of midazolam was noted to enhance the rate of IK(DR) inactivation. On the basis of minimal binding scheme, midazolam-induced block of IK(DR) was quantitatively provided with a dissociation constant of 9.8 µM. Recovery of IK(DR) from inactivation in the presence of midazolam was fitted by a single exponential. midazolam had no effect on M-type or erg-mediated K(+) current in these cells. Midazaolam (30 µM) suppressed the peak amplitude of voltage-gated Na(+) current (INa) with no change in the current-voltage relationships of this current. Inactivation kinetics of INa remained unaltered in the presence of this agent. In current-clamp configuration, midazolam (30 µM) prolonged the duration of action potentials (APs) and reduce AP amplitude. Similarly, in differentiated NG108-15 cells, the exposure to midazolam also suppressed IK(DR) with a concomitant increase in current inactivation. Midazolam can act as an open-channel blocker of delayed-rectifier K(+) channels in these cells. The synergistic blocking effects on IK(DR) and INa may contribute to the underlying mechanisms through which midazolam affects neuronal function in vivo.
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Affiliation(s)
- Edmund Cheung So
- Department of Anesthesia, Tainan Municipal An-Nan Hospital, China Medical University, 66# Cheung Ho Road, An-Nan District, Tainan, Taiwan; Department of Anesthesia, China Medical University, 91# Hsueh-Shih Road, Taichung, Taiwan; Department of Cell Biology and Anatomy, Cheng Kung University, 1# University Road, Tainan City, Taiwan; Department of Anesthesia, Taishan Medical University, 619 Chang Cheng Road, Taian 271016, Shandong Province, PR China; Department of Anesthesia, Nan Shan branch of Gilu Hospital, Shandong University, Shandong Province, PR China.
| | - King Chuen Wu
- Department of Anesthesiology, Eda-Hospital/I-Shou University, 1# Yida Road, Jiaosu Village, Yanchao District, Kaohsiung, Taiwan.
| | - Feng Chen Kao
- Department of Orthopedic Surgery, E-Da Hospital/I-Shou University, 1# Yida Road, Jiaosu Village, Yanchao District, Kaohsiung, Taiwan.
| | - Sheng Nan Wu
- Department of Physiology, National Cheng Kung University, 1# University Road, Tainan City, Taiwan.
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Involvement of the GABAergic system in the anxiolytic-like effect of the flavonoid ellagic acid in mice. Eur J Pharmacol 2013; 710:49-58. [DOI: 10.1016/j.ejphar.2013.04.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/30/2013] [Accepted: 04/03/2013] [Indexed: 11/20/2022]
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Pharmacological modulation of functional connectivity: α2-adrenergic receptor agonist alters synchrony but not neural activation. Neuroimage 2011; 60:436-46. [PMID: 22209807 DOI: 10.1016/j.neuroimage.2011.12.026] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 12/07/2011] [Accepted: 12/14/2011] [Indexed: 11/24/2022] Open
Abstract
Correlative low frequency fluctuations in functional MRI (fMRI) signals across brain regions at rest have been taken as a measure of functional connectivity to map large-scale neural networks; however, the neural origin is still not clear. Receptor-targeted pharmacological manipulation could elucidate the role of neuroreceptor systems in resting-state functional connectivity to provide another perspective on the mechanism. In this study, the dose-dependent effects of an α(2)-adrenergic receptor agonist, medetomidine, on brain activation and functional connectivity were investigated. Forepaw stimulation-induced activation and resting-state fluctuation in the rat somatosensory cortices and caudate putamen were measured using the blood oxygenation level dependent (BOLD) fMRI. The results showed significant dose-dependent suppression of inter-hemispheric correlation but not the amplitude in the somatosensory areas, while the stimulation-induced activation in the same areas remained unchanged. To clarify the potential change in the hemodynamic response caused by the vasoconstrictive effect of medetomidine, the resting perfusion fluctuation was studied by arterial spin labeling and showed similar results as the BOLD. This suggests that the oxygen metabolic rate and hence the neural activity may not be affected by medetomidine but only the synchrony between brain regions was suppressed. Furthermore, no change in functional connectivity with medetomidine dosages was seen in the caudate putamen, a region with much lower α(2)-receptor density. These results indicate that resting-state signal correlation may reflect underlying neuroreceptor activity and a potential role of the adrenergic system in the functional connectivity.
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de Carvalho RSM, Duarte FS, de Lima TCM. Involvement of GABAergic non-benzodiazepine sites in the anxiolytic-like and sedative effects of the flavonoid baicalein in mice. Behav Brain Res 2011; 221:75-82. [DOI: 10.1016/j.bbr.2011.02.038] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/12/2011] [Accepted: 02/26/2011] [Indexed: 01/28/2023]
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Moreira ELG, Rial D, Duarte FS, De Carvalho CR, Horst H, Pizzolatti MG, Prediger RDS, Ribeiro-do-Valle RM. Central nervous system activity of the proanthocyanidin-rich fraction obtained from Croton celtidifolius in rats. J Pharm Pharmacol 2010; 62:1061-8. [DOI: 10.1111/j.2042-7158.2010.01124.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Objectives
The aim of the present study was to evaluate the possible neurobehavioural effects in rats of the proanthocyanidin-rich fraction (PRF) isolated from the bark of Croton celtidifolius (Euphorbiaceae).
Methods
Adult Wistar rats were treated with the PRF (0.3–30 mg/kg) and evaluated in different behavioural paradigms classically used for the screening of drugs with psychoactive effects.
Key findings
Acute intraperitoneal (i.p.) administration of PRF decreased spontaneous locomotor activity (open field arena and activity cage), enhanced the duration of ethyl ether-induced hypnosis, increased the latency to the first convulsion induced by pentylenetetrazole (60 mg/kg, i.p.) and attenuated apomorphine-induced (0.5 mg/kg, i.p.) stereotyped behaviour. In lower doses, PRF (0.3 or 3 mg/kg, i.p.) increased the frequency of open arm entries in the elevated plus-maze test.
Conclusions
The present findings suggest that the systemic administration of PRF induces a wide spectrum of behavioural alterations in rats, consistent with the putative existence of hypnosedative, anticonvulsant and anxiolytic compounds.
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Affiliation(s)
- Eduardo L G Moreira
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Daniel Rial
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Filipe S Duarte
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | | | - Heros Horst
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Moacir G Pizzolatti
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Rui D S Prediger
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil
- Centro de Neurociências Aplicadas (CeNAp), Universidade Federal de Santa Catarina, Florianópolis, Brazil
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Nasrallah FA, Griffin JL, Balcar VJ, Rae C. Understanding your inhibitions: effects of GABA and GABAAreceptor modulation on brain cortical metabolism. J Neurochem 2009; 108:57-71. [DOI: 10.1111/j.1471-4159.2008.05742.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Duarte FS, Duzzioni M, Mendes BG, Pizzolatti MG, De Lima TCM. Participation of dihydrostyryl-2-pyrones and styryl-2-pyrones in the central effects of Polygala sabulosa (Polygalaceae), a folk medicine topical anesthetic. Pharmacol Biochem Behav 2007; 86:150-61. [PMID: 17275892 DOI: 10.1016/j.pbb.2006.12.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 12/20/2006] [Accepted: 12/22/2006] [Indexed: 10/23/2022]
Abstract
This study was undertaken to evaluate the psychopharmacological effects in mice of the hydroethanolic extract (HE), aqueous, hexane and ethyl acetate (EA) fractions, and 6-methoxy-7-prenyloxycoumarin, three dihydrostyryl-2-pyrones and three styryl-2-pyrones isolated from Polygala sabulosa (Polygalaceae), a folk medicine used as a topical anesthetic. In the elevated plus-maze test (EPM), the HE of P. sabulosa and its EA induced an increase in the percentage of time spent on, and in the frequency of entries into the open arms, as well as in the number of unprotected head-dipping, besides a reduction in protected stretch-attend postures, thus indicating an anxiolytic-like profile of action for this plant species. In the hypnosis test, HE and EA enhanced the duration of pentobarbital-induced sleep, a hypnosedative effect confirmed in ethyl ether-induced hypnosis. Moreover, both preparations reduced the duration of the first convulsion induced by pentylenetetrazol, besides decreasing the severity of the seizures. The dihydrostyryl-2-pyrones (1) and (3) as well as styryl-2-pyrones (4) and (7), centrally administered, showed a similar anxiolytic-like effect in the EPM test, while the dihydrostyryl-2-pyrone (2) and styryl-2-pyrone (5) were inactive at the doses used here. These results suggest that P. sabulosa is a herbal medicine which possesses anxiolytic-like, hypnosedative and anticonvulsant effects, and these central effects can be attributed to the presence of the dihydrostyryl-2-pyrone and styryl-2-pyrone compounds.
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Affiliation(s)
- Filipe Silveira Duarte
- Laboratory of Neuropharmacology, Department of Pharmacology, Universidade Federal de Santa Catarina, 88049-900, Florianópolis, SC, Brazil
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Chang CW, Qu B, Hong Z, Gao GD. Potentiation of inhibitory amino acid receptors-mediated responses by lanthanum in rat sacral dorsal commissural neurons. Neurotoxicol Teratol 2006; 28:657-63. [PMID: 17045457 DOI: 10.1016/j.ntt.2006.08.006] [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] [Received: 04/23/2006] [Revised: 08/23/2006] [Accepted: 08/23/2006] [Indexed: 11/19/2022]
Abstract
Lanthanum is one of rare earth cations with extremely active chemical property and has been reported to influence neuronal transmitter systems. To date, little attention has been directed towards the sacral dorsal commissural nucleus (SDCN), which serves as a relay of sensory information from the pelvic viscera in the spinal cord. Therefore, the effect of lanthanum on the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and glycine (Gly) responses in neurons acutely dissociated from the rat SDCN was investigated using the nystatin-perforated patch-recording configuration under voltage-clamp conditions. At a holding potential of -40 mV, La(3+) reversibly potentiated GABA (3 microM)-activated currents (I(GABA)) in a concentration-dependent manner over the concentration range of 10 microM to 30 mM, with the EC(50) value of 67.3+/-16.4 microM. Similarly, La(3+) reversibly potentiated glycine (10 microM)-activated currents (I(Gly)) in a concentration-dependent manner over the concentration range of 1 microM to 1 mM, with the EC(50) value of 52.3+/-10.9 microM. The effects of La(3+) on I(GABA) and I(Gly) were voltage-independent. Moreover, both of the potentiations were not use-dependent and were overcome by increasing the concentration of agonist. Our results indicate that La(3+) potentiates the inhibitory amino acid receptors-mediated responses in SDCN, which may reduce the transmission of the pelvic visceral information. The information provided by this work may help to elucidate the mechanisms and effects of lanthanum on brain functions.
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Affiliation(s)
- Chong-Wang Chang
- Institute of Functional Brain Disorders, Fourth Military Medical University, Xi'an 710032, China
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Hong Z, Wang DS. Potentiation, activation and blockade of GABAA receptors by etomidate in the rat sacral dorsal commissural neurons. Neuroscience 2005; 132:1045-53. [PMID: 15857709 DOI: 10.1016/j.neuroscience.2005.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2004] [Revised: 01/30/2005] [Accepted: 02/02/2005] [Indexed: 11/22/2022]
Abstract
Etomidate (ET), an imidazole general anesthetic, has been medically widely used. Recent evidence suggests that the inhibitory neurotransmitter GABA receptor may be one of the important molecular target(s) of general anesthetics. Up to date, little attention has been directed toward the sacral dorsal commissural nucleus (SDCN), which serves as a relay of sensory information from the pelvic viscera in the spinal cord. Therefore, the effect of ET on GABA(A) receptor function in neurons acutely dissociated from the SDCN was investigated using the nystatin-perforated patch-recording configuration under voltage-clamp conditions. At a holding potential of -40 mV, ET (above 10 microM) induced an inward ET-activated current (I(ET)) with the EC(50) value of 33 +/- 3 microM, which was reversibly blocked by bicuculline and picrotoxin. The reversal potential of I(ET) was close to the Cl(-) equilibrium potential. ET also displayed a biphasic modulatory effect on GABA responses. At lower concentrations (0.1-100 microM), ET reversibly potentiated GABA (1 microM)-activated Cl(-) currents in a bell-shaped manner, with the maximal facilitative effect at 10 microM, whereas at concentrations >100 microM, the peak of the ET-induced current was suppressed in the absence or presence of GABA (1 microM). These results suggest that in SDCN, in addition to the potentiation of GABA(A) receptor-mediated responses at low concentrations and the direct activation of GABA(A) receptors at moderate concentrations as expected, ET produced a fast blocking action at high concentrations. The general anesthetic-induced effects in SDCN, at least the potentiation of GABA responses, may significantly contribute to anesthesia of pelvic viscera during the general anesthesia.
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Affiliation(s)
- Z Hong
- Department of Anatomy and K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an, Shaanxi, China
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