Previous experimental studies have shown that intracerebroventricular (i.c.v.) injection of the GABAA receptor antagonist, bicuculline methiodide, results in marked increases in blood pressure due to an increase in sympathetic nervous system activity. It is well recognized that the central cholinergic system is also involved in the regulation of blood pressure. In the present study, we examined the role of brain acetylcholine in the pressor response induced by bicuculline methiodide in conscious Sprague-Dawley rats. I.c.v. (0.05, 0.3 and 0.5 nmol) and intrahypothalamic (40 pmol) administration of bicuculline methiodide produced blood-pressure increases in a dose-dependent manner. Hemicholinium-3 was given i.c.v. 1 h prior to bicuculline methiodide. The depletion of brain acetylcholine was demonstrated by the suppression of physostigmine-induced pressor responses, but blood pressure increases in response to carbachol remained unchanged. The pressor responses to bicuculline methiodide in animals pre-treated with hemicholinium-3 were significantly higher than those seen in saline-pre-treated groups. Likewise, bicuculline methiodide, at a dose that did not alter blood pressure alone, caused pressor responses in rats pre-treated with the nicotinic receptor antagonist, mecamylamine, whereas the muscarinic receptor antagonist, atropine, was ineffective in this respect. In conclusion, it seems likely that endogenous brain acetylcholine has a modulator role on GABAA receptor-mediated blood-pressure control via nicotinic receptors.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s0014-2999(96)00744-3 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Piriform cortex is an ictogenic trigger zone in the primate brain.
Epilepsia
December 2024
Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia, USA.
Objective: Area tempestas, a functionally defined region in the anterior piriform cortex, was identified as a crucial ictogenic trigger zone in the rat brain in the 1980s. However, whether the primate piriform cortex can trigger seizures remains unknown. Here, in a nonhuman primate model, we aimed to localize a similar trigger zone in the piriform cortex and, subsequently, evaluated the ability of focal inhibition of the substantia nigra pars reticulata (SNpr) to suppress the evoked seizures.
View Article and Find Full Text PDFOptimizing GABA receptor antagonism for the induction of long-term potentiation in the mouse and rat dentate gyrus in vitro.
J Neurophysiol
July 2024
Division of Medical Sciences and Institute for Aging and Lifelong Health, University of Victoria, Victoria, British Columbia, Canada.
The reliable induction of long-term potentiation (LTP) in the dentate gyrus (DG) in vitro requires the blockade of the γ-aminobutyric acid A (GABA) receptor. In these studies we examined the effectiveness of the specific GABA receptor antagonist bicuculline methiodide (BMI) in facilitating LTP in the DG from hippocampal slices obtained from either C57Bl/6 mice or Sprague-Dawley rats, two species commonly used for electrophysiology. In the C57Bl/6 mice, maximal short-term potentiation and LTP in the DG were produced with a concentration of 5 µM BMI.
View Article and Find Full Text PDFSwallowing-like activity elicited in neonatal rat medullary slice preparation.
Brain Res
August 2024
First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan.
Swallowing is induced by a central pattern generator in the nucleus tractus solitarius (NTS). We aimed to create a medullary slice preparation to elucidate the neural architecture of the central pattern generator of swallowing (Sw-CPG) and record its neural activities. Experiments were conducted on 2-day-old Sprague-Dawley rats (n = 46).
View Article and Find Full Text PDFMicroglia trigger the structural plasticity of GABAergic neurons in the hippocampal CA1 region of a lipopolysaccharide-induced neuroinflammation model.
Exp Neurol
December 2023
Department of Ophthalmology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China. Electronic address:
It is well-established that microglia-mediated neuroinflammatory response involves numerous neuropsychiatric and neurodegenerative diseases. While the role of microglia in excitatory synaptic transmission has been widely investigated, the impact of innate immunity on the structural plasticity of GABAergic inhibitory synapses is not well understood. To investigate this, we established an inflammation model using lipopolysaccharide (LPS) and observed a prolonged microglial response in the hippocampal CA1 region of mice, which was associated with cognitive deficits in the open field test, Y-maze test, and novel object recognition test.
View Article and Find Full Text PDFReduced mechanical hypersensitivity by inhibition of the amygdala in experimental neuropathy: Sexually dimorphic contribution of spinal neurotransmitter receptors.
Brain Res
December 2022
Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland. Electronic address:
Here we studied spinal neurotransmitter mechanisms involved in the reduction of mechanical hypersensitivity by inhibition of the amygdaloid central nucleus (CeA) in male and female rats with spared nerve injury (SNI) model of neuropathy. SNI induced mechanical hypersensitivity that was stronger in females. Reversible blocking of the CeA with muscimol (GABA receptor agonist) induced a reduction of mechanical hypersensitivity that did not differ between males and females.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!