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Hernández A, González-Sierra C, Zetina ME, Cifuentes F, Morales MA. Age-Dependent Changes in the Occurrence and Segregation of GABA and Acetylcholine in the Rat Superior Cervical Ganglia. Int J Mol Sci 2024; 25:2588. [PMID: 38473838 DOI: 10.3390/ijms25052588] [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: 10/11/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 03/14/2024] Open
Abstract
The occurrence, inhibitory modulation, and trophic effects of GABA have been identified in the peripheral sympathetic nervous system. We have demonstrated that GABA and acetylcholine (ACh) may colocalize in the same axonal varicosities or be segregated into separate ones in the rat superior cervical ganglia (SCG). Neurotransmitter segregation varies with age and the presence of neurotrophic factors. Here, we explored age-dependent changes in the occurrence and segregation of GABA and ACh in rats ranging from 2 weeks old (wo) to 12 months old or older. Using immunohistochemistry, we characterized the expression of L-glutamic acid decarboxylase of 67 kDa (GAD67) and vesicular acetylcholine transporter (VAChT) in the rat SCG at 2, 4, 8, 12 wo and 12 months old or older. Our findings revealed that GAD67 was greater at 2 wo compared with the other ages, whereas VAChT levels were greater at 4 wo than at 12 wo and 12 months old or older. The segregation of these neurotransmitters was more pronounced at 2 and 4 wo. We observed a caudo-rostral gradient of segregation degree at 8 and 12 wo. Data point out that the occurrence and segregation of GABA and ACh exhibit developmental adaptative changes throughout the lifetime of rats. We hypothesize that during the early postnatal period, the increase in GABA and GABA-ACh segregation promotes the release of GABA alone which might play a role in trophic actions.
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Affiliation(s)
- Alfredo Hernández
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Constanza González-Sierra
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - María Elena Zetina
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Fredy Cifuentes
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Miguel Angel Morales
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
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Ganglionic Long-Term Potentiation in Prehypertensive and Hypertensive Stages of Spontaneously Hypertensive Rats Depends on GABA Modulation. Neural Plast 2019; 2019:7437894. [PMID: 31737063 PMCID: PMC6815531 DOI: 10.1155/2019/7437894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/08/2019] [Accepted: 09/06/2019] [Indexed: 01/31/2023] Open
Abstract
The sympathetic nervous system (SNS) regulates body functions in normal and pathological conditions and is characterized by the presence of a neuroplastic phenomenon, termed ganglionic long-term potentiation (gLTP). In hypertension, either in spontaneously hypertensive rats (SHR) or in humans, sympathetic hyperfunction, such as elevated SNS outflow and changes in synaptic plasticity have been described. Because enhanced SNS outflow is detected in the hypertensive stage and, more importantly, in the prehypertensive phase of SHR, here we explored whether synaptic plasticity, particularly gLTP, was modified in the superior cervical ganglia (SCG) of prehypertensive SHR. Furthermore, considering that GABA modulates sympathetic synaptic transmission and gLTP in Wistar rats, we studied whether GABA might modulate gLTP expression in SHR. We characterized gLTP in the SCG of young prehypertensive 6-week-old (wo) and adult hypertensive (12 wo) SHR and in the SCG of Wistar Kyoto (WKy) normotensive control rats of the same ages. We found that gLTP was expressed in 6 wo SHR, but not in 12 wo rats. By contrast, in WKy, gLTP was expressed in 12 wo, but not in 6 wo rats. We also found that gLTP depends on GABA modulation, as blockade of GABA-A subtype receptors with its antagonist bicuculline unmasked gLTP expression in adult SHR and young WKy. We propose that (1) activity-dependent changes in synaptic efficacy are altered not only during hypertension but also before its onset and (2) GABA may play a modulatory role in the changes in synaptic plasticity in SHR, because the blockade of GABA-A receptors unmasked the expression of gLTP. These early changes in neuroplasticity and GABA modulation of gLTP could be part of the sympathetic hyperfunction observed in hypertension.
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Shi Y, Li Y, Yin J, Hu H, Xue M, Li X, Cheng W, Wang Y, Li X, Wang Y, Tan J, Yan S. A novel sympathetic neuronal GABAergic signalling system regulates NE release to prevent ventricular arrhythmias after acute myocardial infarction. Acta Physiol (Oxf) 2019; 227:e13315. [PMID: 31116911 PMCID: PMC6813916 DOI: 10.1111/apha.13315] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 05/09/2019] [Accepted: 05/16/2019] [Indexed: 11/30/2022]
Abstract
AIM Overactivation of the sympathetic nerve may lead to severe ventricular arrhythmias (VAs) after myocardial infarction (MI). Thus, targeting sympathetic nerve activity is an effective strategy to prevent VAs clinically. The superior cervical ganglion (SCG), the extracardiac sympathetic ganglion innervating cardiac muscles, has been found to have a GABAergic signalling system, the physiological significance of which is obscure. We aimed to explore the functional significance of SCG post MI and whether the GABAergic signal system is involved in the process. METHODS Adult male Sprague-Dawley rats were divided into seven different groups. Rats in the MI groups underwent ligation of the left anterior descending coronary artery. All animals were used for electrophysiological testing, renal sympathetic nerve activity (RSNA) testing, and ELISA. Primary SCG sympathetic neurons were used for the in vitro study. RESULTS The GABAA receptor agonist muscimol significantly decreased the ATP-induced increase in intracellular Ca2+ (P < 0.05). GABA treatment in MI rats significantly attenuated the level of serum and cardiac norepinephrine (NE; P < 0.05). Sympathetic activity and inducible VAs were also lower in MI + GABA rats than in MI rats (P < 0.05). Knockdown of the GABAA Rs β2 subunit (GABAA Rβ2 ) in the SCG of MI rats increased the NE levels in serum and cardiac tissue, RSNA and inducible VAs compared with vehicle shRNA (P < 0.05). CONCLUSION The GABAergic signalling system is functionally expressed in SCG sympathetic neurons, and activation of this system suppresses sympathetic activity, thereby facilitating cardiac protection and making it a potential target to alleviate VAs.
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Affiliation(s)
- Yugen Shi
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Yan Li
- Medical Research CenterShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
- School of MedicineShandong UniversityShandongChina
| | - Jie Yin
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Hesheng Hu
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Mei Xue
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Xiaolu Li
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Wenjuan Cheng
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Ye Wang
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Xinran Li
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Yu Wang
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Jiayu Tan
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
| | - Suhua Yan
- Department of CardiologyShandong Provincial Qianfoshan Hospital, Shandong UniversityShandongChina
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Brown DA. Norman Bowery's discoveries about extrasynaptic and asynaptic GABA systems and their significance. Neuropharmacology 2017; 136:3-9. [PMID: 29128306 DOI: 10.1016/j.neuropharm.2017.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/04/2017] [Indexed: 11/26/2022]
Abstract
Before discovering the GABA-B receptor, Norman Bowery completed a series of studies on an extrasynaptic or asynaptic "GABA system" in the rat superior cervical sympathetic ganglion. First, he discovered an uptake system for GABA in neuroglial cells in the ganglia and in peripheral nerves, with a different substrate specificity than that in neurons. Second, he showed that accumulated GABA in sympathetic glial cells was metabolized to succinate by a transaminase enzyme. Third, he provided detailed structure-activity information about compounds activating an extrasynaptic GABA-A receptor on neurons in the rat sympathetic ganglion. Fourth, he showed that some amino acid substrates for the neuroglial transporter could indirectly stimulate neurons by releasing GABA from adjacent glial cells, and that GABA could also be released from neuroglial cells by membrane depolarization. In this review, these discoveries are briefly described and updated and some of their implications assessed. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- David A Brown
- Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E 6BT, UK.
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Barnerssoi M, May PJ, Horn AKE. GABAergic innervation of the ciliary ganglion in macaque monkeys - A light and electron microscopic study. J Comp Neurol 2017; 525:1517-1531. [PMID: 27864939 DOI: 10.1002/cne.24145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/19/2016] [Accepted: 10/23/2016] [Indexed: 11/09/2022]
Abstract
The vertebrate ciliary ganglion (CG) is a relay station in the parasympathetic pathway activating the iris sphincter and ciliary muscle to mediate pupillary constriction and lens accommodation, respectively. While the postganglionic motoneurons in the CG are cholinergic, as are their inputs, there is evidence from avian studies that GABA may also be involved. Here, we used light and electron microscopic methods to examine the GABAergic innervation of the CG in Macaca fascicularis monkeys. Immunohistochemistry for the gamma aminobutyric acid synthesizing enzyme glutamic acid decarboxylase (GAD) and choline acetyltransferase (ChAT) revealed that all CG neurons are contacted by ChAT-positive terminals. A subpopulation of 17.5% of CG neurons was associated with terminal boutons expressing GAD-immunoreactivity in addition. Double-labeling for GAD and synaptophysin confirmed that these were synaptic terminals. Electron microscopic analysis in conjunction with GABA-immunogold staining showed that (1) GAD-positive terminals mainly target dendrites and spines in the perisomatic neuropil of CG neurons; (2) GABA is restricted to a specific terminal type, which displays intermediate features lying between classically excitatory and inhibitory endings; and (3) if a CG neuron is contacted by GABA-positive terminals, virtually all perisomatic terminals supplying it show GABA immunoreactivity. The source of this GABAergic input and whether GABA contributes to a specific CG function remains to be investigated. Nevertheless, our data indicate that the innervation of the ciliary ganglion is more complex than previously thought, and that GABA may play a neuromodulatory role in the control of lens or pupil function. J. Comp. Neurol. 525:1517-1531, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Miriam Barnerssoi
- Institute of Anatomy and Cell Biology I, Ludwig-Maximilian Universität, Munich, Germany
| | - Paul J May
- Departments of Neurobiology and Anatomical Sciences, Ophthalmology, and Neurology, University of Mississippi Medical Center, Jackson, MS, 39216
| | - Anja K E Horn
- Institute of Anatomy and Cell Biology I, Ludwig-Maximilian Universität, Munich, Germany
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Elinos D, Rodríguez R, Martínez LA, Zetina ME, Cifuentes F, Morales MA. Segregation of Acetylcholine and GABA in the Rat Superior Cervical Ganglia: Functional Correlation. Front Cell Neurosci 2016; 10:91. [PMID: 27092054 PMCID: PMC4823314 DOI: 10.3389/fncel.2016.00091] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/23/2016] [Indexed: 11/13/2022] Open
Abstract
Sympathetic neurons have the capability to segregate their neurotransmitters (NTs) and co-transmitters to separate varicosities of single axons; furthermore, in culture, these neurons can even segregate classical transmitters. In vivo sympathetic neurons employ acetylcholine (ACh) and other classical NTs such as gamma aminobutyric acid (GABA). Herein, we explore whether these neurons in vivo segregate these classical NTs in the superior cervical ganglia of the rat. We determined the topographical distribution of GABAergic varicosities, somatic GABAA receptor, as well as the regional distribution of the segregation of ACh and GABA. We evaluated possible regional differences in efficacy of ganglionic synaptic transmission, in the sensitivity of GABAA receptor to GABA and to the competitive antagonist picrotoxin (PTX). We found that sympathetic preganglionic neurons in vivo do segregate ACh and GABA. GABAergic varicosities and GABAA receptor expression showed a rostro-caudal gradient along ganglia; in contrast, segregation exhibited a caudo-rostral gradient. These uneven regional distributions in expression of GABA, GABAA receptors, and level of segregation correlate with stronger synaptic transmission found in the caudal region. Accordingly, GABAA receptors of rostral region showed larger sensitivity to GABA and PTX. These results suggest the presence of different types of GABAA receptors in each region that result in a different regional levels of endogenous GABA inhibition. Finally, we discuss a possible correlation of these different levels of GABA modulation and the function of the target organs innervated by rostral and caudal ganglionic neurons.
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Affiliation(s)
- Diana Elinos
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
| | - Raúl Rodríguez
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
| | - Luis Andres Martínez
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
| | - María Elena Zetina
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
| | - Fredy Cifuentes
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
| | - Miguel Angel Morales
- Departamento de Biología Celular and Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Ciudad de México, México
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Oomori Y, Murabayashi H, Kuramoto H, Kawano H, Kato K, Nakagawa C, Sasaki M, Kitamura N, Ishikawa K, Tanaka K. Gamma-aminobutyric acid B Receptor Immunoreactivity in the Mouse Adrenal Medulla. Anat Rec (Hoboken) 2013; 296:971-8. [DOI: 10.1002/ar.22697] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 02/26/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Yukio Oomori
- Division of Anatomy and Physiology; Japanese Red Cross Hokkaido College of Nursing; Kitami Japan
| | - Hiroshi Murabayashi
- Division of Anatomy and Physiology; Japanese Red Cross Hokkaido College of Nursing; Kitami Japan
| | - Hirofumi Kuramoto
- Division of Applied Biological Science; Kyoto Institute of Technology; Kyoto Japan
| | - Hitoshi Kawano
- Division of Function and Morphology for Nursing; Faculty of Medicine; Saga University; Saga Japan
| | - Kanae Kato
- Division of Anatomy and Physiology; Japanese Red Cross Hokkaido College of Nursing; Kitami Japan
| | - Chieko Nakagawa
- Division of Anatomy and Physiology; Japanese Red Cross Hokkaido College of Nursing; Kitami Japan
| | - Motoki Sasaki
- Department of Agriculture and Life Science; Obihiro University of Agriculture and Veterinary Medicine; Obihiro Japan
| | - Nobuo Kitamura
- Department of Agriculture and Life Science; Obihiro University of Agriculture and Veterinary Medicine; Obihiro Japan
| | - Katsushi Ishikawa
- Division of Applied Physiology; School of Nursing; Faculty of Medicine; Asahikawa Medical University; Asahikawa Japan
| | - Kunio Tanaka
- Division of Biomedical Engineering; Hokkaido Medical Technological School; Asahikawa Japan
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Park JC, Song DY, Lee JS, Kong ID, Jeong SW, Lee BH, Kang HS, Cho BP. Expression of GABAA receptor β2/3 subunits in the rat major pelvic ganglion. Neurosci Lett 2006; 403:35-9. [PMID: 16716506 DOI: 10.1016/j.neulet.2006.04.051] [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: 02/15/2006] [Revised: 04/07/2006] [Accepted: 04/18/2006] [Indexed: 10/24/2022]
Abstract
Several pharmacological and physiological studies have suggested that GABA(A) receptors (GABA(A) Rs) may exist in the rat major pelvic ganglion (MPG), a large coalescent pelvic ganglion that contains both sympathetic and parasympathetic components which innervates pelvic organs. However, the presence of GABA(A) R in the MPG has never been demonstrated directly by morphological studies. In the present study, we used immunohistochemistry to demonstrate the existence of GABA(A) R beta2/3 subunits for the first time in the rat MPG. We also analyzed the neurochemical properties of MPG neurons expressing GABA(A) R beta2/3 subunits. GABA(A) R beta2/3-immunoreactive (-IR) neurons occupied 27.4+/-7.0% of the whole neuronal population, and many of these (77.6%) were co-localized with tyrosine hydroxylase (TH). Likewise, most (86.5%) of TH-IR neurons were GABA(A) R beta2/3-positive. GABA(A) R beta2/3 subunits were also expressed in a few VIP- or NOS-IR neurons, the cholinergic or non-adrenergic, non-cholinergic (NANC) neurons. These results suggest that GABA(A) Rs are involved in the modulation of most sympathetic, noradrenergic neurons and also a subset of VIP and NOS neurons of the rat MPG.
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Affiliation(s)
- Jung Cheol Park
- Department of Anatomy, Institute of Basic Medical Science and Industry-Academic Cooperation Foundation, Yonsei University Wonju College of Medicine, 162, Ilsan-dong, Gangwon-do 220-701, South Korea
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Watanabe M, Maemura K, Kanbara K, Tamayama T, Hayasaki H. GABA and GABA receptors in the central nervous system and other organs. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 213:1-47. [PMID: 11837891 DOI: 10.1016/s0074-7696(02)13011-7] [Citation(s) in RCA: 373] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gamma-aminobutyrate (GABA) is a major inhibitory neurotransmitter in the adult mammalian brain. GABA is also considered to be a multifunctional molecule that has different situational functions in the central nervous system, the peripheral nervous system, and in some nonneuronal tissues. GABA is synthesized primarily from glutamate by glutamate decarboxylase (GAD), but alternative pathways may be important under certain situations. Two types of GAD appear to have significant physiological roles. GABA functions appear to be triggered by binding of GABA to its ionotropic receptors, GABA(A) and GABA(C), which are ligand-gated chloride channels, and its metabotropic receptor, GABA(B). The physiological, pharmacological, and molecular characteristics of GABA(A) receptors are well documented, and diversity in the pharmacologic properties of the receptor subtypes is important clinically. In addition to its role in neural development, GABA appears to be involved in a wide variety of physiological functions in tissues and organs outside the brain.
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Nozdrachev AD, Jiménez B, Morales MA, Fateev MM. Neuronal organization and cell interactions of the cat stellate ganglion. Auton Neurosci 2002; 95:43-56. [PMID: 11871785 DOI: 10.1016/s1566-0702(01)00360-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The functional structure of the cat stellate ganglion (SG) and, in particular, its extra- and intraganglionic connections and neuronal organization, were investigated using histochemical, immunohistochemical, morphological and histological methods. Retrograde axonal transport of horseradish peroxidase was used to determine most of the extraganglionic interactions. Of the targets tested, the most extensive efferent connections of the SG were with the stemocleidomastoid muscle, trachea, esophagus and heart. Neurons of the SG also send a small number of postganglionic efferents to the thyroid and stomach. Furthermore, ganglion cells send axons to the spinal ganglia. Several afferent connections of the SG were determined. Sympathetic preganglionic neurons of segments C8-T10 of the spinal cord, sensory neurons of C8-T9 spinal ganglia, intramural ganglia of the thoracic viscera and the reticular formation of the medulla oblongata send their axons to the SG. Intraganglionic interactions of intemeurons with principal ganglionic cells were assumed to occur, based on the presence of interneurons immunoreactive to GABA and substance P. GABA- and substance P-immunoreactive fibers located around a small number of postganglionic neurons were also identified. Morphological study revealed asymmetry between the left and right ganglia: the right ganglion is larger than the left and contains more cells. This asymmetry was also reflected in basic structural parameters of neurons, such as average neuronal area and average diameter of cell somata. The present data has been used to develop a scheme for the basic inter- and intraneuronal connections of the cat SG. This ganglion is a true nervous center, with postganglionic neurons, some of which might be performing sensory functions, and interneurons. The ganglion is connected not only with the spinal cord and spinal ganglia, but also with neurons of the intramural ganglia and, by direct links, with efferent neurons of the medulla oblongata. Thus, the SG may play an essential role in viscera-visceral reflexes.
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Sha L, Miller SM, Szurszewski JH. Electrophysiological effects of GABA on cat pancreatic neurons. Am J Physiol Gastrointest Liver Physiol 2001; 280:G324-31. [PMID: 11171614 DOI: 10.1152/ajpgi.2001.280.3.g324] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In mammalian peripheral sympathetic ganglia GABA acts presynaptically to facilitate cholinergic transmission and postsynaptically to depolarize membrane potential. The GABA effect on parasympathetic pancreatic ganglia is unknown. We aimed to determine the effect of locally applied GABA on cat pancreatic ganglion neurons. Ganglia with attached nerve trunks were isolated from cat pancreata. Conventional intracellular recording techniques were used to record electrical responses from ganglion neurons. GABA pressure microejection depolarized membrane potential with an amplitude of 17.4 +/- 0.7 mV. Electrically evoked fast excitatory postsynaptic potentials were significantly inhibited (5.4 +/- 0.3 to 2.9 +/- 0.2 mV) after GABA application. GABA-evoked depolarizations were mimicked by the GABA(A) receptor agonist muscimol and abolished by the GABA(A) receptor antagonist bicuculline and the Cl(-) channel blocker picrotoxin. GABA was taken up and stored in ganglia during preincubation with 1 mM GABA; beta-aminobutyric acid application after GABA loading significantly (P < 0.05) increased depolarizing response to GABA (15.6 +/- 1.0 vs. 7.8 +/- 0.8 mV without GABA preincubation). Immunolabeling with antibodies to GABA, glial cell fibrillary acidic protein, protein gene product 9.5, and glutamic acid decarboxylase (GAD) immunoreactivity showed that GABA was present in glial cells, but not in neurons, and that glial cells did not contain GAD, whereas islet cells did. The data suggest that endogenous GABA released from ganglionic glial cells acts on pancreatic ganglion neurons through GABA(A) receptors.
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Affiliation(s)
- L Sha
- Department of Physiology and Biophysics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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12
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Abstract
gamma-Aminobutyric acid (GABA), one of the most important neurotransmitters in the brain, is also found in the periphery. GABAA receptors are chloride channels opened by GABA whose presence in the rat superior cervical ganglion has been indicated by functional and binding measurements. We describe the first molecular data on the possible subunit composition of these receptors, detecting mRNAs for 12 subunits (alpha1-5, beta1-3, gamma1-3, delta) by reverse-transcriptase polymerase chain reaction. Preliminary quantitation gave highest levels (in descending order) for the gamma2 (both short and long forms), beta3, gamma3, and alpha1 subunits.
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Affiliation(s)
- Z F Liu
- Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Baltimore, Md. 21201-1559, USA
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Klimaschewski L, Kummer W, Heym C. Localization, regulation and functions of neurotransmitters and neuromodulators in cervical sympathetic ganglia. Microsc Res Tech 1996; 35:44-68. [PMID: 8873058 DOI: 10.1002/(sici)1097-0029(19960901)35:1<44::aid-jemt5>3.0.co;2-s] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cervical sympathetic ganglia represent a suitable model for studying the establishment and plasticity of neurochemical organization in the nervous system since sympathetic postganglionic neurons: (1) express several neuromediators, i.e., short acting transmitters, neuropeptide modulators and radicals, in different combinations; (2) receive synaptic input from a limited number of morphologically and neurochemically well-defined neuron populations in the central and peripheral nervous systems (anterograde influence on phenotype); (3) can be classified morphologically and neurochemically by the target they innervate (retrograde influence on phenotype); (4) regenerate readily, making it possible to study changes in neuromediator content after axonal lesion and their possible influence on peripheral nerve regeneration; (5) can be maintained in vitro in order to investigate effects of soluble factors as well as of membrane bound molecules on neuromediator expression; and (6) are easily accessible. Acetylcholine and noradrenaline, as well as neuropeptides and the recently discovered radical, nitric oxide, are discussed with respect to their localization and possible functions in the mammalian superior cervical and cervicothoracic (stellate) paravertebral ganglia. Furthermore, mechanisms regulating transmitter synthesis in sympathetic neurons in vivo and in vitro, such as soluble factors, cell contact or electrical activity, are summarized, since modulation of transmitter synthesis, release and metabolism plays a key role in the neuronal response to environmental influences.
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Affiliation(s)
- L Klimaschewski
- Institute of Anatomy and Cell Biology, University of Heidelberg, Federal Republic of Germany
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14
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González Burgos GR, Biali FI, Nicola Siri LC, Cardinali DP. Effect of gamma-aminobutyric acid on synaptic transmission and long-term potentiation in rat superior cervical ganglion. Brain Res 1994; 658:1-7. [PMID: 7834329 DOI: 10.1016/s0006-8993(09)90002-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of gamma-aminobutyric acid (GABA) on synaptic transmission in rat superior cervical ganglion (SCG) was assessed in vitro by extracellular recording. Postganglionic compound action potentials (CAPs) triggered by preganglionic stimulation were blocked in a reversible and concentration-dependent fashion by short, 60 s long, superfusion with GABA (IC50 = 39.3 microM), with the GABAA agonist muscimol (IC50 = 8.7 microM) or with the GABAB agonist baclofen (IC50 = 145 microM). Responses to GABA and muscimol, but not to baclofen, exhibited desensitization after 5 min long superfusions with the drugs. In a long-term potentiation (LTP) paradigm, the degree of potentiation found 30 min after a tetanic train of stimuli (20 Hz for 20 s) was strongly inhibited by GABA (100-250 microM), when superfused at the time of tetanic stimulus or shortly thereafter. The effect of GABA on SCG LTP was mimicked by muscimol but not by baclofen. The results are compatible with the view that GABA exerts overall inhibitory effects in rat SCG, including transmission blockade of single impulses (through activation of GABAA and GABAB receptors) and impairment of activity-dependent potentiation of nicotinic transmission (through activation of GABAA receptors).
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Affiliation(s)
- G R González Burgos
- Departamento de Fisiología, Facultad de Medicina, Unidersidad de Buenos Aires, Argentina
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15
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Stapelfeldt WH, Parkman HP, Szurszewski JH. The electrophysiological effects of endogenous GABA in the guinea-pig inferior mesenteric ganglion. J Physiol 1993; 471:175-89. [PMID: 7907143 PMCID: PMC1143957 DOI: 10.1113/jphysiol.1993.sp019896] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. GABA receptor-modulating drugs and intracellular recording techniques were used to determine the functional significance of peripheral afferent GABA-containing nerves projecting from the distal colon to sympathetic neurones in the inferior mesenteric ganglion of the guinea-pig. 2. GABAA receptor-modulating drugs added selectively to the inferior mesenteric ganglion side of a two-compartment bath had pronounced effects on on-going colonic afferent cholinergic synaptic input. Bicuculline (20 microM) decreased the amplitude and frequency of fast excitatory postsynaptic potentials (EPSPs) by 40% whereas diazepam (5 microM) increased cholinergic input by 43%. Neither drug had any effect on the resting membrane potential or membrane input resistance of ganglion cells. 3. Bicuculline (20 microM) significantly reduced, whereas diazepam (5 microM) significantly enhanced, distension-induced increases in nicotinic fast EPSPs and action potentials. 4. Slow EPSPs evoked by colonic distension were not affected by bicuculline or diazepam. 5. Manual voltage clamp of the postsynaptic depolarizing response to exogenous GABA revealed GABA-induced presynaptic facilitation of colonic afferent but not central preganglionic efferent cholinergic synaptic input. 6. The data suggest that endogenously released GABA participates in on-going colo-colonic reflex activity by acting on presynaptic GABAA receptors to facilitate release of acetylcholine from colonic mechanosensory nerves.
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Affiliation(s)
- W H Stapelfeldt
- Department of Physiology and Biophysics, Mayo Clinic, Rochester, MN 55905
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16
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Oomori Y, Iuchi H, Nakaya K, Tanaka H, Ishikawa K, Satoh Y, Ono K. Gamma-aminobutyric acid (GABA) immunoreactivity in the mouse adrenal gland. HISTOCHEMISTRY 1993; 100:203-13. [PMID: 8244771 DOI: 10.1007/bf00269093] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gamma-aminobutyric acid (GABA) immunoreactivity was revealed by immunocytochemistry in the mouse adrenal gland at the light and electron microscopic levels. Groups of weakly or faintly GABA immunoreactive chromaffin cells were often seen in the adrenal medulla. By means of immunohistochemistry combined with fluorescent microscopy, these GABA immunoreactive chromaffin cells showed noradrenaline fluorescence. The immunoreaction product was seen mainly in the granular cores of these noradrenaline cells. These results suggest the co-existence of GABA and noradrenaline within the chromaffin granules. Sometimes thick or thin bundles of GABA immunoreactive nerve fibers with or without varicosities were found running through the cortex directly into the medulla. In the medulla, GABA immunoreactive varicose nerve fibers were numerous and were often in close contact with small adrenaline cells and large ganglion cells; a few, however, surrounded clusters of the noradrenaline cells, where membrane specializations were formed. Single GABA immunoreactive nerve fibers, and thin or thick bundles of the immunoreactive varicose nerve fibers ran along the blood vessels in the medulla. The immunoreaction deposits were observed diffusely in the axoplasm and in small agranular vesicles of the GABA immunoreactive nerve fibers. Since no ganglion cells with GABA immunoreactivity were found in the adrenal gland, the GABA immunoreactive nerve fibers are regarded as extrinsic in origin.
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Affiliation(s)
- Y Oomori
- Department of Anatomy, Asahikawa Medical College, Japan
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17
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Wolff JR, Kása P, Dobó E, Römgens HJ, Párducz A, Joó F, Wolff A. Distribution of GABA-immunoreactive nerve fibers and cells in the cervical and thoracic paravertebral sympathetic trunk of adult rat: evidence for an ascending feed-forward inhibition system. J Comp Neurol 1993; 334:281-93. [PMID: 8366197 DOI: 10.1002/cne.903340209] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Neurochemical and immunohistochemical evidence suggests that the superior cervical ganglion (SCG) contains all components of a gamma-aminobutyric acid (GABA)ergic transmission system, which includes GABAergic axons of unknown origin. The number of nerve fibers with and without GABA-like immunoreactivity was determined in interganglionic connectives at all cervical and thoracic levels of the paravertebral sympathetic trunk. In addition, the distribution of GABA-immunoreactive (IR) neurons was established within the ganglion chain and compared with the relative frequency of principal neurons richly innervated by GABA-IR axon terminals. The following results were obtained: 1) the total number of nerve fibers in cross sections did not significantly vary between the cervical levels, but it increased steadily from upper to lower thoracic segments; 2) in contrast, the number of GABA-IR fibers decreased from the cervical sympathetic trunk below the SCG (approximately 300 fibers) down to the seventh to tenth thoracic ganglion, below which no such fiber was seen; 3) GABA-IR nerve fibers originate from a subclass of GABA-IR cells; these are small, bipolar neurons with predominantly ascending, unmyelinated axon-like processes; 4) the number of principal neurons richly innervated by GABA-IR nerve fibers decreased from the SCG to the upper thoracic ganglia, and was very small below; and 5) apart from basket-like innervation, GABA-IR axons also formed diffuse networks around GABA-negative principal neurons predominantly in cervical and upper thoracic ganglia. These data suggest that the GABAergic innervation of paravertebral sympathetic ganglia is more complex than previously suspected. What appears as preganglionic afferents from several spinal segments (C8-Th7) innervate GABAergic neurons in the sympathetic trunk which have ascending axons and focus their inhibitory effects on the cervical sympathetic ganglia, predominantly the SCG. These data suggest that GABAergic small interganglionic neurons form a feed-forward inhibition system, which may be driven by multisegmental spinal input in the paravertebral sympathetic ganglion chain.
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Affiliation(s)
- J R Wolff
- Department of Anatomy, University of Göttingen, Germany
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18
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Wolff JR, Joó F, Kása P. Modulation by GABA of neuroplasticity in the central and peripheral nervous system. Neurochem Res 1993; 18:453-61. [PMID: 8474568 DOI: 10.1007/bf00967249] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apart from being a prominent (inhibitory) neurotransmitter that is widely distributed in the central and peripheral nervous system, gamma-aminobutyric acid (GABA) has turned out to exert trophic actions. In this manner GABA may modulate the neuroplastic capacity of neurons and neuron-like cells under various conditions in situ and in vitro. In the superior cervical ganglion (SCG) of adult rat, GABA induces the formation of free postsynaptic-like densities on the dendrites of principal neurons and enables implanted foreign (cholinergic) nerves to establish functional synaptic contacts, even while preexisting connections of the preganglionic axons persist. Apart from postsynaptic effects, GABA inhibits acetylcholine release from preganglionic nerve terminals and changes, at least transiently, the neurochemical markers of cholinergic innervation (acetylcholinesterase and nicotinic receptors). In murine neuroblastoma cells in vitro, GABA induces electron microscopic changes, which are similar in principle to those seen in the SCG. Both neuroplastic effects of GABA, in situ and in vitro, could be mimicked by sodium bromide, a hyperpolarizing agent. In addition, evidence is available that GABA via A- and/or B-receptors may exert direct trophic actions. The regulation of both types of trophic actions (direct, receptor-mediated vs. indirect, bioelectric activity dependent) is discussed.
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Affiliation(s)
- J R Wolff
- Department of Anatomy, University of Göttingen, Federal Republic of Germany
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19
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Abstract
The autonomic nervous system is divided into the sympathetic, parasympathetic and enteric subdivisions. The present review is focussed upon the highly specialized reflex organization and neurochemistry of sympathetic parasympathetic neurons. The currently available informations allow to conclude that autonomic control of each peripheral target tissue is specifically regulated under normal conditions but nevertheless able to respond to altered conditions by changes in neural activity and mediator expression.
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Affiliation(s)
- W Kummer
- Institute for Anatomy and Cell Biology, Ruprecht-Karls-University, Heidelberg, Germany
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20
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Párducz A, Dobó E, Joó F, Wolff JR. Termination pattern and fine structural characteristics of GABA- and [Met]enkephalin-containing nerve fibers and synapses in the superior cervical ganglion of adult rat. Neuroscience 1992; 49:963-71. [PMID: 1436490 DOI: 10.1016/0306-4522(92)90372-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Morphological features of nerve fibers and synapses containing GABA and [Met]enkephalin were studied at the light and electron microscopic levels in the superior cervical ganglia of rats by pre- and postembedding immunohistochemistry. Both GABA and [Met]enkephalin immunoreactivities were found in varicose nerve fibers, forming diffuse networks which were denser in the rostral than in the caudal part of each ganglion. For both antigens rich and basket-like innervation was observed around some of the principal neurons. The GABA-immunoreactive fibers were evenly stained, while in case of [Met]enkephalin-positive nerve fibers the varicosities showed intensive immunopositivity only. Postembedding immunochemistry revealed that both inhibitory substances were located in axon varicosities which established asymmetric synapses of Gray I type. Fine structural investigation revealed that GABA-like immunoreactivity was confined in the nerve endings to the clear synaptic vesicles of 40 nm diameter, whereas the immunogold particles, indicating the occurrence of [Met]enkephalin, were located over the large dense-cored vesicles of 120 nm diameter. The clear and dense-cored vesicles were, however, mixed in the nerve endings labeled by either neurotransmitter substance. Interestingly, the [Met]enkephalin-immunopositive axon terminals were found, consequently, in synaptic contacts with dendrites containing dense bodies in a row underlying the postsynaptic membrane thickening. Since nerve terminals with GABA-like immunoreactivity established synapses of Gray I type without such subjunctional bodies, one can reasonably assume that, in spite of similarities in termination pattern, there is no co-existence of GABA and enkephalin in the axons in the superior cervical ganglion.
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Affiliation(s)
- A Párducz
- Institute of Biophysics, Biological Research Center, Szeged, Hungary
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21
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Szabat E, Soinila S, Häppölä O, Linnala A, Virtanen I. A new monoclonal antibody against the GABA-protein conjugate shows immunoreactivity in sensory neurons of the rat. Neuroscience 1992; 47:409-20. [PMID: 1641131 DOI: 10.1016/0306-4522(92)90255-z] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A monoclonal antibody, 115AD5, was raised against GABA coupled to bovine serum albumin. The monoclonal antibody 115AD5 also reacted with other GABA-protein conjugates. The specificity of the monoclonal antibody was corroborated by enzyme-linked immunoassay, dot-immunobinding experiments and immunostaining of rat cerebellum sections. The monoclonal antibody 115AD5 could successfully be applied on Vibratome and cryostat sections using either indirect immunofluorescence or peroxidase techniques. In rat cerebellar cortex the monoclonal antibody 115AD5 gave an intense immunoreaction in stellate cells, in Golgi neurons, and in basket cells and their processes around Purkinje cell bodies. Purkinje cell dendrites showed GABA immunoreactivity while the cell bodies were non-reactive or only weakly reactive. There was labelling in some nuclei of Purkinje cells. GABA immunoreactivity was also found in dot-like structures in the granular layer. A large population of sensory neurons in rat thoracic and lumbar spinal dorsal root ganglia presented an intense immunoreactivity for the monoclonal antibody 115AD5. Nerve bundles immunoreactive for GABA were also seen in these ganglia. In the trigeminal ganglion, a major population of sensory neurons and some of their processes presented immunoreactivity for GABA. In the sensory nodose ganglion of the vagus nerve, many neuronal cell bodies and some fibres were immunoreactive for GABA. Ligation of the vagus nerve caudal to the ganglion resulted in an increased GABA immunoreactivity in neuronal somata of the ganglion, as well as in nerve fibres on the ganglionic side of the ligature. The present results suggest that in the rat, a population of sensory neurons in thoracic and lumbar spinal dorsal root ganglia, as well as in the trigeminal and nodose ganglia contain GABA. The presence of GABA immunoreactivity in these neurons raises the possibility of a neurotransmitter or modulator role.
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Affiliation(s)
- E Szabat
- Department of Anatomy, University of Helsinki, Finland
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22
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González Burgos G, Rosenstein RE, Cardinali DP. Neurochemical evidence for a neuronal GABAergic system in the rat sympathetic superior cervical ganglion. J Neural Transm (Vienna) 1992; 89:27-40. [PMID: 1358123 DOI: 10.1007/bf01245349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Some characteristics of gamma aminobutyric acid (GABA) uptake and release in rat superior cervical ganglion (SCG) were investigated. Kinetic analysis of GABA uptake indicated the existence of both high affinity (Km = 18.6 microM) and low affinity (Km = 485 microM) uptake systems. 3H-GABA influx was decreased by inhibitors of glial (beta-alanine), neuronal (2,4-diaminobutyric acid, DABA), or glial and neuronal GABA uptake (nipecotic acid). 3H-GABA efflux was elicited by K+ depolarization in a dose-dependent manner, an effect unaltered by severing the preganglionic nerve fibers. Superfusion of SCG explants with DABA or beta-alanine resulted in increased 3H-GABA efflux from tissue, an effect amplified by the absence of calcium in the superfusion medium. 3H-GABA loading in the presence of DABA, but not in the presence of beta-alanine, resulted in abolition of K(+)-elicited 3H release. At 20 mM, but not at 50 mM K+, the release of 3H-GABA was inhibited by replacing Ca2+ by Mg2+ and by adding EGTA, or by incubating SCG in the presence of the Ca(2+)-channel blocker verapamil. Veratrine evoked GABA release in Ca(2+)-independent manner. None of several putative SCG autacoids or agonists (nicotine, muscarine, norepinephrine, dopamine, serotonin, baclofen, muscimol) significantly modified GABA release.
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Affiliation(s)
- G González Burgos
- Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina
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23
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Kasa P, Dobo E, Wolff JR. Cholinergic innervation of the mouse superior cervical ganglion: light- and electron-microscopic immunocytochemistry for choline acetyltransferase. Cell Tissue Res 1991; 265:151-8. [PMID: 1913775 DOI: 10.1007/bf00318149] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The cholinergic innervation of the mouse superior cervical ganglion was investigated by means of immunocytochemistry using a well-characterized monoclonal antibody against choline acetyltransferase (ChAT). Immunopositive nerve fibers entered the superior cervical ganglion from the cervical sympathetic trunk. Light-microscopically, these fibers appeared to be heterogeneously distributed among the principal ganglion cells. The rostral part of the ganglion contained more ChAT-positive fibers then the middle or the caudal one. The axons branched several times before forming numerous varicosities. Most of the ChAT-stained fibers and varicosities aggregated in glomerula-like neuropil structures that were surrounded by principal ganglion cell bodies, whereas others were isolated or formed little bundles among principle neurons. None of the neurons or other cell types in the ganglion exhibited ChAT-positivity. ChAT-immunoreactive fibers disappeared from the ganglion 5 or 13 days after transection of the cervical sympathetic trunk. At the ultrastructural level, most axon terminals and synapses showed ChAT-immunoreactivity. An ultrastructural analysis indicated that immunostained synapses occurred directly on the surface of neuronal soma (1.8%) and dendritic shafts (17.6%). Synapses were often seen on soma spines (18.4%) and on dendritic spines (62.2%). All immunoreactive synapses were of the asymmetric type. The results provide immunocytochemical evidence for a heterogeneous cholinergic innervation of the ganglion and the principal neurons.
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Affiliation(s)
- P Kasa
- Central Research Laboratory, Albert Szent-Györgyi Medical University, Szeged, Hungary
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24
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Imai H, Okuno T, Wu JY, Lee TJ. GABAergic innervation in cerebral blood vessels: an immunohistochemical demonstration of L-glutamic acid decarboxylase and GABA transaminase. J Cereb Blood Flow Metab 1991; 11:129-34. [PMID: 1983997 DOI: 10.1038/jcbfm.1991.15] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The presence of GABAergic innervation in cerebral arteries of several species was investigated by an immunohistochemical method using antibodies against glutamic acid decarboxylase (GAD) and GABA transaminase (GABA-T). Both GAD and GABA-T immunoreactivities were found to be associated with large bundles and single fibers in the adventitial layer of arteries examined. The density and distribution pattern of both GAD- and GABA-T-immunoreactive fibers were found to be comparable at most regions examined. Both fibers were found to be most dense in the anterior cerebral artery and its adjacent part of the circle of Willis. Several peripheral arteries were found to receive very sparse or no GAD- and GABA-T-immunoreactive fibers. Superior cervical ganglionectomy did not appreciably affect the distribution of both fibers. Cold-storage denervation, however, resulted in a drastic decrease in both fibers. At ultrastructural levels, both GAD- and GABA-T-immunoreactive nerve profiles were found to be very close to the smooth muscle cells. These results demonstrate the presence of a potentially functional GABAergic innervation in cerebral circulation. On few occasions, GAD immunoreactivities were also found in some endothelial cells, suggesting that a nonneuronal GABA system may also be present in cerebral arteries.
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Affiliation(s)
- H Imai
- Department of Pharmacology, Southern Illinois University, School of Medicine, Springfield 62708-9990
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25
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Dobó E, Kása P, Joó F, Wenthold RJ, Wolff JR. Structures with GABA-like and GAD-like immunoreactivity in the cervical sympathetic ganglion complex of adult rats. Cell Tissue Res 1990; 262:351-61. [PMID: 2076539 DOI: 10.1007/bf00309890] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The distribution of gamma-aminobutyric acid (GABA)-like and glutamate decarboxylase (GAD)-like immunoreactivity was studied in the cervical sympathetic ganglion complex of rats, including the intermediate and inferior cervical ganglia and the uppermost thoracic ganglion. GABA-positive axons may enter the ganglion complex via its caudal end. Others apparently arise from small GABA-positive cell bodies which are scattered among principal neurons, within clusters of SIF cells and in bundles of GABA-negative axons. The majority of these cells is located in the lower half of the ganglion complex. Principal neurons did not react with antibodies against GABA or GAD. An unevenly distributed mesh-work of GABA-immunoreactive axons was seen in each of the ganglia. Immunoreactive axons formed numerous varicosities. Some of them were aggregated in a basket-like form around a subpopulation of GABA-negative principal ganglion cell bodies. Electron-microscopic immunocytochemistry revealed that GABA-positive nerve fibers establish asymmetric synaptic junctions with dendritic and somatic spines of principal neurons, whereas postsynaptic densities are inconspicuous or absent on dendritic shafts and somata. The results suggest that in the cervical sympathetic ganglion complex principal neurons are not GABAergic, but are innervated by axons which react with both antibodies against GAD and/or GABA antibodies and originate from a subpopulation of small neurons.
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Affiliation(s)
- E Dobó
- Central Research Laboratory, Albert Szent-Györgyi Medical University, Szeged, Hungary
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26
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Affiliation(s)
- S L Erdö
- Department of Anatomy, Georg August University, Göttingen, F.R.G
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27
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Abstract
Gamma-aminobutyric acid (GABA) and its receptors are found in a wide range of peripheral tissues, including parts of the peripheral nervous system, endocrines, and non-neural tissues such as smooth muscle and the female reproductive system. In all these, both GABAA- and GABAB-receptor types are found, with good evidence for a physiological role in the gut, pancreatic islets and the urinary bladder. In some tissues, the pharmacology of GABA-induced actions is quite atypical and should be further explored with the newer ligands and modulators for GABAA- and GABAB-receptors.
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Affiliation(s)
- J Ong
- Department of Anaesthesia and Intensive Care, University of Adelaide, South Australia
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28
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Dobó E, Kása P, Wenthold RJ, Wolff JR. Pronase treatment increases the staining intensity of GABA-immunoreactive structures in the paravertebral sympathetic ganglia. HISTOCHEMISTRY 1989; 93:13-8. [PMID: 2482273 DOI: 10.1007/bf00266841] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A novel tissue preparation technique for improving gamma-aminobutyric acid (GABA) immunocytochemistry has been developed. The influence of the glutaraldehyde concentration in the fixative and the effect of pronase treatment on the GABA immunostaining were tested. This method includes fixation with a high concentration of glutaraldehyde, gelatin embedding and treatment of the sections with pronase. In sympathetic (paravertebral) ganglia and their connectives, the most intense and specific immunoreaction was obtained with the following procedure: immersion fixation in 5% glutaraldehyde, infiltration and embedding in 15% gelatin, secondary fixation of the samples with 4% formaldehyde, floating frozen sections and digestion with 0.1% pronase for 15-20 min. With this technique, the GABA-containing structures (cells and nerve fibers with varicosities forming basket-like networks around some principal neurons) were selectively labeled. The data presented suggest that (1) a high concentration (5%) of glutaraldehyde in the primary fixative is necessary to preserve a large proportion of the GABA content; (2) this glutaraldehyde fixation partly masks the GABA immunoreactivity; and (3) this masking may be overcome by a proteolytic treatment preceding the immunostaining. This method has been extensively tested for the light microscopic visualization of GABA-containing tissue components in the sympathetic ganglion chain, but it may probably also be used for the immunocytochemical detection of other small molecules in other parts of the nervous system.
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Affiliation(s)
- E Dobó
- Central Research Laboratory, Albert Szent-Györgyi Medical University, Szeged, Hungary
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29
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von Bartheld CS, Rubel EW. Transient GABA immunoreactivity in cranial nerves of the chick embryo. J Comp Neurol 1989; 286:456-71. [PMID: 2778102 DOI: 10.1002/cne.902860405] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The distribution and time course of gamma-aminobutyric acid (GABA) immunoreactivity was investigated in the cranium of the chick embryo from 2 to 16 days of incubation (E2-16). A fraction of nerve fibers transiently stains GABA-positive in all cranial motor nerves and in the vestibular nerve. Cranial motor nerves stain GABA-positive from E4 to E11, including neuromuscular junctions at E8-11; labeled fibers are most frequent in the motor trigeminal root (E6-9.5). Substantial GABA staining is present from E4 to E10 in a subpopulation (1-2%) of vestibular ganglion cells. Their peripheral processes are labeled in the vestibular endorgan, predominantly in the posterior crista. Some GABA-positive fibers are present in the olfactory nerve (after E5) and in the optic nerve (after E9.5); their immunoreactivity persists throughout the period investigated. Transient GABA immunoreactivity follows "pioneer" fiber outgrowth and coincides with the formation of early synaptic contacts. GABA-containing neurons may change their neuronal phenotype (loss of GABA expression) or they may be eliminated by embryological cell death. Periods of cell death were determined in cranial ganglia and motor nuclei by aggregations of pycnotic cells in the same embryonic material. The periods of embryonic cell death partly coincide with transient GABA immunoreactivity. The function(s) of transient GABA expression is unknown. Some lines of evidence suggest that GABA has neurotrophic functions in developing cranial nerves or their target tissue. In the developing neuromuscular junction, GABA may be involved in the regulation of acetylcholine receptors.
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Affiliation(s)
- C S von Bartheld
- Hearing Development Laboratories, University of Washington, Seattle 98195
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30
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Wright LL, Luebke JI. Somatostatin-, vasoactive intestinal polypeptide- and neuropeptide Y-like immunoreactivity in eye- and submandibular gland-projecting sympathetic neurons. Brain Res 1989; 494:267-75. [PMID: 2570622 DOI: 10.1016/0006-8993(89)90595-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Studies combine the use of the retrograde tracer, fluorogold, and immunocytochemical staining to determine whether superior cervical ganglion (SCG) neurons projecting to the iris or submandibular gland (SMG) in adult male and female rats show distinctive immunoreactivity to somatostatin (SS), vasoactive intestinal polypeptide (VIP), or neuropeptide Y. Overall, more SMG-projecting neurons than eye-projecting neurons contain VIP-like immunoreactivity (VIP-LI), and more eye-projecting neurons than SMG-projecting neurons contain SS-LI and VIP-LI. Thus, postganglionic neurons of the SCG that project to specific target tissues are heterogeneous in their peptide content, and there are differences in the pattern of peptide-immunoreactivity between neurons projecting to these two target tissues. In addition, the results indicate that there may be gender differences in the expression of these neuropeptides.
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Affiliation(s)
- L L Wright
- Department of Anatomy, Boston University School of Medicine, MA 02118
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31
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Wolff JR, Kasa P, Dobo E, Wenthold RJ, Joo F. Quantitative analysis of the number and distribution of neurons richly innervated by GABA-immunoreactive axons in the rat superior cervical ganglion. J Comp Neurol 1989; 282:264-73. [PMID: 2708597 DOI: 10.1002/cne.902820208] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The superior cervical ganglion of rats contains a considerable number of nerve fibers with GABA-like immunoreactivity which show a nonuniform distribution within the ganglion. The topography of these fibers has been analyzed by using antibodies raised against GABA-BSA-glutaraldehyde complexes. GABA-positive axons and axon varicosities accumulated around a subpopulation of principal ganglion cells forming basketlike patterns. These neurons richly innervated by GABA-positive axons (RIG-neurons) in turn were aggregated in patches with strong immunoreactivity. The size and packing density of the patches containing RIG-neurons and GABA-positive axons approaching them had rostral-to-caudal and medial-to-lateral gradients. Similar patterns were found in right and left ganglia. In five ganglia, a quantitative analysis revealed on average 1,344 RIG-neurons per ganglion representing about 5% of the total neuron population, with small variations (standard deviation 122) despite the highly variable shape of the ganglia. The distribution of RIG-neurons resembles that of neurons sending their axons into the internal carotid nerve. To check this possible correlation, HRP was injected into the eye and applied to the transected external carotid nerve. Double staining for the retrogradely transported peroxidase and GABA immunohistochemistry revealed that RIG-neurons formed a small subpopulation of retrogradely labelled neurons in both experiments. This suggests that RIG-neurons innervate various target organs. This conclusion is in agreement with the observation that RIG-neurons also exist in other sympathetic ganglia. Data presented suggest that sympathetic ganglion cells can be classified on the basis of non-uniform innervation patterns formed by axons that use different neurotransmitters.
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Affiliation(s)
- J R Wolff
- Department of Anatomy, University of Göttingen, Federal Republic of Germany
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Ahonen M, Joh TH, Wu JY, Häppölä O. Immunocytochemical localization of L-glutamate decarboxylase and catecholamine-synthesizing enzymes in the retroperitoneal sympathetic tissue of the newborn rat. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1989; 26:89-96. [PMID: 2566632 DOI: 10.1016/0165-1838(89)90156-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The localization of L-glutamate decarboxylase (GAD), the enzyme synthesizing gamma-aminobutyric acid, was studied in newborn rat retroperitoneal sympathetic tissue, i.e. the main retroperitoneal paraganglion, adrenal medullae and abdominal sympathetic ganglia using the indirect immunofluorescence method. The coexistence of GAD with the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) was analyzed in consecutive sections or by staining one section consecutively with different antisera. GAD immunoreactivity was observed only in some cell types of each organ studied. In the main retroperitoneal paraganglion, the small, intensely TH-immunoreactive, paraganglion-type cells were GAD-immunoreactive, while the larger moderately TH-immunoreactive, neuron-like cells were non-reactive for GAD. In the adrenal medulla, GAD immunoreactivity was localized only in the adrenaline-synthesizing, PNMT-immunoreactive chromaffin cells. The noradrenaline-synthesizing, i.e. the TH-immunoreactive cells with no PNMT immunoreactivity, were non-reactive for GAD. In the abdominal sympathetic ganglia, some small intensely TH-immunoreactive cells were GAD-immunoreactive, while the principal neurons were non-reactive for GAD. These results provide immunohistochemical evidence that GAD is present and is colocalized with catecholamine-synthesizing enzymes in various sympathetic tissues of the newborn rat. The present results indicate that GAD is localized in adrenaline-synthesizing cells of all the sympathetic tissues studied. A fraction of noradrenaline-synthesizing cells of retroperitoneal sympathetic tissues, excluding the adrenal medulla, also contains GAD.
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Affiliation(s)
- M Ahonen
- Department of Anatomy, University of Helsinki, Finland
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Dobó E, Kása P, Wenthold RJ, Joó F, Wolff JR. Evidence for GABAergic fibers entering the superior cervical ganglion of rat from the preganglionic nerve trunk. HISTOCHEMISTRY 1989; 92:133-6. [PMID: 2475472 DOI: 10.1007/bf00490232] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The origin of gamma-aminobutyric acid immunoreactive (GABA-IR) nerve fibers present in the superior cervical ganglion (SCG) of rat was investigated. With immunocytochemical techniques many nerve fibers showed GABA-like positivity in the cervical sympathetic trunk, whereas similar staining could not be revealed in the internal carotid nerve or in the external carotid nerve. Ligation of the cervical sympathetic trunk for 24 h resulted a dramatic reduction in the staining density in the ganglion and in the cervical sympathetic trunk distal to the ligature. After transection of the preganglionic nerve fibers for eleven days or more, very few fibers staining for GABA were seen in the ganglion. The immunohistochemical results suggest that a major source of GABA within the SCG is a population of GABAergic axons entering from the preganglionic trunk.
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Affiliation(s)
- E Dobó
- Central Research Laboratory, Albert Szent-Györgyi Medical University, Szeged, Hungary
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34
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Erdö SL, Joo F, Wolff JR. Immunohistochemical localization of glutamate decarboxylase in the rat oviduct and ovary: further evidence for non-neural GABA systems. Cell Tissue Res 1989; 255:431-4. [PMID: 2924343 DOI: 10.1007/bf00224128] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The distribution of L-glutamate decarboxylase (GAD), a major biosynthetic enzyme for gamma-aminobutyric acid (GABA), was examined in the oviduct and ovary of the rat by means of an immunohistochemical technique. The polyclonal antiserum raised against brain GAD showed specific immunoreaction in some non-neuronal elements of the sex organs. In the oviduct, the inner layer of the mucosa was predominantly labelled. The selective distribution of GAD immunoreactivity in epithelial cells of the oviduct is consistent with former findings for GABA-like immunoreactivity in the same organ, indicating that the GAD-catalyzed reaction may be a major biosynthetic pathway for GABA even in these cells. In the ovary, vacuole-like formations within the follicular fluid and oocytes showed intense, specific staining. The occurrence of GAD immunoreactivity inside developing ovarian follicles including the oocyte may suggest a role for GABA related to follicular development and certain functions concerning the ovum.
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Affiliation(s)
- S L Erdö
- Department of Anatomy, Georg August University, Göttingen, Federal Republic of Germany
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35
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Abstract
The uptake and K+-evoked release of [3H] gamma-aminobutyric acid (GABA) was examined in tissue slices from rat gastric antrum. Active [3H]GABA accumulation was observed that could only be partially inhibited by L-diaminobutyric acid (L-DABA), a blocker of neuronal GABA uptake. The L-DABA-insensitive uptake component was saturable, sodium-dependent and of high affinity. Moreover, [3H]GABA could be released from this L-DABA-resistant pool by a high K+ concentration. It is concluded that a releasable, non-neuronal GABA pool, which may have some functional significance, is present in the gastric antrum.
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Affiliation(s)
- S L Erdö
- Pharmacological Research Centre, Chemical Works of G. Richter Ltd., Budapest, Hungary
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Kása P, Joó F, Dobó E, Wenthold RJ, Ottersen OP, Storm-Mathisen J, Wolff JR. Heterogeneous distribution of GABA-immunoreactive nerve fibers and axon terminals in the superior cervical ganglion of adult rat. Neuroscience 1988; 26:635-44. [PMID: 3173691 DOI: 10.1016/0306-4522(88)90170-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The distribution of axons and axon varicosities containing GABA was studied in the superior cervical ganglion of rat by light and electron microscopic immunohistochemistry. Two different polyclonal antibodies were used, which had been made against GABA conjugated by glutardialdehyde to bovine serum albumin. GABA-like immunoreactivity occurred in many axons within the cervical sympathetic trunk and in axons and axon varicosities around the principal nerve cells in the superior cervical ganglion. GABA-positive axons were intermingled with non-stained axons, except for a small group of fibers in the trunk where the staining was absent. The rostral part of the ganglion and some scattered patches were more densely innervated by GABA-positive axons than the middle and caudal parts. Within dense areas, some of the large ganglion cells were abundantly surrounded by GABA-positive nerve fibers, while the vicinity of others was devoid of any immunoreactive axon terminals. None of the principal ganglion cells contained GABA-like immunoreactivity, although a class of small cells scattered within the ganglion was stained. Transection of the cervical sympathetic trunk for 11 days caused the disappearance of GABA-like positivity from most of the fibers, and only very little GABA-like staining was revealed in some small cells, which resembled satellite cells. Ultrastructurally, the GABA-positive nerve fibers were unmyelinated. However, their terminal branches and varicosities accumulated around the perikarya and dendrites of certain principal ganglion cells were partly wrapped in glial processes. The present results provide evidence that the superior cervical ganglion of adult rat receives a significant number of GABA-positive axons from the cervical sympathetic trunk and that these axons provide an innervation which is heterogeneously distributed within the superior cervical ganglion and on ganglionic cells. The source and function of the GABA-positive axons remain to be elucidated.
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Affiliation(s)
- P Kása
- Central Research Laboratory, Medical University, Szeged, Hungary
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Karhula T, Häppölä O, Joh T, Wu JY. Localization of L-glutamate decarboxylase immunoreactivity in the major pelvic ganglion and in the coeliac-superior mesenteric ganglion complex of the rat. HISTOCHEMISTRY 1988; 90:255-60. [PMID: 2906637 DOI: 10.1007/bf00495968] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The localization of L-glutamate decarboxylase (GAD), the GABA-synthesizing enzyme, was studied in the rat major pelvic ganglion and in the coeliac-superior mesenteric ganglion complex by indirect immunofluorescence technique with a specific antiserum raised in rabbits. GAD immunoreactivity was demonstrated in small cells of these ganglia. The GAD-immunoreactive small cells were 10-20 microns in diameter and formed clusters or occurred as solitary cells. The principal neurons were non-reactive but they were surrounded by immunoreactive processes. Studies on colocalization of GAD with tyrosine hydroxylase (TH), the rate-limiting enzyme of the catecholamine synthesis, in the major pelvic ganglion and in the coeliac-superior mesenteric ganglion complex indicated that all GAD-immunoreactive small cells were also labelled with TH. In the major pelvic ganglion all TH-immunoreactive SIF cells were also immunoreactive for GAD. However, in the coeliac-superior mesenteric ganglion complex there occurred TH-immunoreactive small cells which showed no immunoreactivity to GAD. It is suggested that the small GAD-immunoreactive cells represent small intensely fluorescent (SIF) cells.
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Affiliation(s)
- T Karhula
- Department of Anatomy, University of Helsinki, Finland
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Davidoff MS, Schulze W. Coexistence of GABA- and choline acetyltransferase (ChAT)-like immunoreactivity in the hypoglossal nucleus of the rat. HISTOCHEMISTRY 1988; 89:25-33. [PMID: 2835342 DOI: 10.1007/bf00496580] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Single and sequential double immunocytochemical techniques were applied to localize gamma-aminobutyric acid (GABA)- and choline acetyltransferase (ChAT)- like immunoreactivity (-LI) in the hypoglossal nucleus of the rat. After subsequential double staining a relatively high number of hypoglossal motor neurons showed the coexistence of both ChAT- and GABA-LI. Coexistence of both substances was also revealed in the axons of the hypoglossal nerve situated within the medulla oblongata. Cells showing only ChAT- or GABA-LI were also observed. Differences in immunostaining between the different cell groups of the hypoglossal nucleus were established. Following axotomy of the right hypoglossal nerve, a decrease or loss of the immunoreactivity for both ChAT and GABA in the motor neurons was established until the 3rd week after the operation. The results obtained do not give evidence on the origin of the GABA-like immunoreactive material and its functional significance in the cholinergic neurons. It can be only speculated that the GABA-like material is either taken up from the intercellular space or is synthesized by the ChAT-LI nerve cells. Functionally, the importance of GABA for the synthesis of gamma-hydroxybutyrate (a novel neurotransmitter candidate) and its postsynaptic transmitter action or presynaptic regulatory action (through autoreceptors in the membrane of the nerve endings) on the release of acetylcholine (ACh) should be taken into consideration.
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Affiliation(s)
- M S Davidoff
- Regeneration Research Laboratory, Bulgarian Academy of Sciences, Sofia
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Maggi CA, Santicioli P, Giuliani S, Furio M, Conte B, Meli P, Gragnani L, Meli A. The effects of baclofen on spinal and supraspinal micturition reflexes in rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1987; 336:197-203. [PMID: 2825042 DOI: 10.1007/bf00165805] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. The effect of (+/-)-baclofen on micturition reflexes was investigated in urethane-anaesthetized rats. A 'low' dose of (+/-)-baclofen (0.5 mg/kg i.v.) barely affected the early phase of the transurethral cystometrogram (CMG) which involves activation of a spinal vesico-vesical excitatory reflex. 2. At a higher dose (2.5 mg/kg i.v.) (+/-)-baclofen suppressed both the spinal and supraspinal components of the bladder response to transurethral saline filling. 3. When the bladder was filled by the transvesical route a series of regular voiding cycles was obtained which are due to activation of a supraspinal vesico-vesical excitatory reflex. In this model, voiding efficiency of the rat bladder was markedly reduced even after a low dose of (+/-)-baclofen (0.5 mg/kg) and almost suppressed at 2.5 mg/kg. 4. (+/)-Baclofen reduction of voiding efficiency was mainly ascribable to an inhibitory effect on the expulsive phase of the voiding cycle which, in rats, depends critically upon the activation of a reflex which induces a twitch-like contraction of urethral/periurethral skeletal muscles. 5. (+/-)-Baclofen produced a small inhibition of the pinching-induced somatovesical excitatory reflex. (+/-)-Baclofen (2.5 mg/kg i.v.) produced also a marked but transient inhibition of bladder contractions induced by preganglionic nerve stimulation. However the time course of this effect was markedly shorter as compared to the long lasting suppression of voiding cycle observed with this same dose of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C A Maggi
- Pharmacology Department, Research Laboratories, A. Menarini Pharmaceuticals, Florence, Italy
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Eugène D. Fast non-cholinergic depolarizing postsynaptic potentials in neurons of rat superior cervical ganglia. Neurosci Lett 1987; 78:51-6. [PMID: 3039421 DOI: 10.1016/0304-3940(87)90560-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
After the blockade of cholinergic transmission, stimulation of the preganglionic sympathetic trunk elicited fast depolarizing postsynaptic potentials (PSPs) in rat superior cervical ganglia. At 50 min, their amplitude measured intracellularly was 6.9 +/- 1.7 mV and their duration 25.9 +/- 7.6 ms (mean +/- S.D., n = 9 ganglia). The extracellular electrical activity recorded from the postganglionic internal carotid nerve was monophasic and equal to 4.0 +/- 2.2% of the normal activity (mean +/- S.D., n = 12 ganglia). The effects on these PSPs of some postsynaptic receptor antagonists have been tested. Bicuculline decreased the amplitude of the PSPs as well as that of the monophasic extracellular activity, suggesting that GABA could mediate these non-cholinergic synaptic potentials.
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