GABA&lt;sub&gt;A&lt;/sub&gt; Receptor Subunit mRNAs in Rat Superior Cervical Ganglia

Liu, Zhi Fang; Burt, David R.

doi:10.1159/000028268

Cited by 4 publications

(2 citation statements)

References 46 publications

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“…The presence of GABA A R β2/3 subunits in the rat major pelvic ganglion was demonstrated using immunohistochemistry by Park et al ( 2006 ). The presence of mRNAs for at least 12 subunits of the GABA A R has been described in the rat SCG (Liu and Burt, 1999 ).…”

Section: Discussionmentioning

confidence: 99%

Segregation of Acetylcholine and GABA in the Rat Superior Cervical Ganglia: Functional Correlation

Elinos

Rodríguez

Martínez

et al. 2016

Front. Cell. Neurosci.

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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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Section: Discussionmentioning

confidence: 99%

Segregation of Acetylcholine and GABA in the Rat Superior Cervical Ganglia: Functional Correlation

Elinos

Rodríguez

Martínez

et al. 2016

Front. Cell. Neurosci.

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“…Since the cell bodies of most superior cervical ganglion neurons are well‐known to respond strongly to GABA by opening Cl – ‐permeable, bicuculline‐ and picrotoxin sensitive GABA A channels with a reversal potential near −42 mV , it is not surprising that they also express GABA A channels where they terminate in the pineal gland. The most abundant GABA A subunits in the superior cervical ganglion are (in order) γ 2, β3, γ 3, and α 1 . However, we are confident that our electrical records are from pinealocytes rather than, for example, interstitial cells or nerve fibers since isolated living pinealocytes are easy to recognize and patch clamp because of their round shape and higher number than other cell types in the gland , and after 2 days of dispersed culture, all broken nerve terminals should have degenerated .…”

Section: Discussionmentioning

confidence: 89%

GABAergic signaling in the rat pineal gland

Hou

Benitez

Jung

et al. 2016

Journal of Pineal Research

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Pinealocytes secrete melatonin at night in response to norepinephrine released from sympathetic nerve terminals in the pineal gland. The gland also contains many other neurotransmitters whose cellular disposition, activity, and relevance to pineal function are not understood. Here we clarify sources and demonstrate cellular actions of the neurotransmitter γ-aminobutyric acid (GABA) using Western blotting and immunohistochemistry of the gland and electrical recording from pinealocytes. GABAergic cells and nerve fibers, defined as containing GABA and the synthetic enzyme GAD67, were identified. The cells represent a subset of interstitial cells while the nerve fibers were distinct from the sympathetic innervation. The GABAA receptor subunit α1 was visualized in close proximity of both GABAergic and sympathetic nerve fibers as well as fine extensions among pinealocytes and blood vessels. The GABAB1 receptor subunit was localized in the interstitial compartment but not in pinealocytes. Electrophysiology of isolated pinealocytes revealed that GABA and muscimol elicit strong inward chloride currents sensitive to bicuculline and picrotoxin, clear evidence for functional GABAA receptors on the surface membrane. Applications of elevated potassium solution or the neurotransmitter acetylcholine depolarized the pinealocyte membrane potential enough to open voltage-gated Ca2+ channels leading to intracellular calcium elevations. GABA repolarized the membrane and shut off such calcium rises. In 48–72-h cultured intact glands, GABA application neither triggered melatonin secretion by itself nor affected norepinephrine-induced secretion. Thus strong elements of GABA signaling are present in pineal glands that make large electrical responses in pinealocytes, but physiological roles need to be found.

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γ‐Aminobutyric acid‐containing sympathetic preganglionic neurons in rat thoracic spinal cord send their axons to the superior cervical ganglion

Ito

Hioki

Nakamura

et al. 2007

J of Comparative Neurology

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Gamma-aminobutyric acid (GABA)-containing fibers have been observed in the rat superior cervical ganglion (SCG) and, to a lesser extent, in the stellate ganglion (STG). The aim of present study is to clarify the source of these fibers. No cell body showed mRNAs for glutamic acid decarboxylases (GADs) or immunoreactivity for GAD of 67 kDa (GAD67) in the cervical sympathetic chain. Thus, GABA-containing fibers in the ganglia are suggested to be of extraganglionic origin. GAD67-immunoreactive fibers were found not in the dorsal roots or ganglia, but in the ventral roots, so GABA-containing fibers in the sympathetic ganglia were considered to originate from the spinal cord. Furthermore, almost all GAD67-immunoreactive fibers in the sympathetic ganglia showed immunoreactivity for vesicular acetylcholine transporter, suggesting that GABA was utilized by some cholinergic preganglionic neurons. This was confirmed by the following results. 1) After injection of Sindbis/palGFP virus into the intermediolateral nucleus, some anterogradely labeled fibers in the SCG were immunopositive for GAD67. 2) After injection of fluorogold into the SCG, some retrogradely labeled neurons in the thoracic spinal cord were positive for GAD67 mRNA. 3) When the ventral roots of the eighth cervical to the fourth thoracic segments were cut, almost all GAD67- and GABA-immunoreactive fibers disappeared from the ipsilateral SCG and STG, suggesting that the vast majority of GABA-containing fibers in those ganglia were of spinal origin. Thus, the present findings strongly indicate that some sympathetic preganglionic neurons are not only cholinergic but also GABAegic.

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GABA<sub>A</sub> Receptor Subunit mRNAs in Rat Superior Cervical Ganglia

Cited by 4 publications

References 46 publications

Segregation of Acetylcholine and GABA in the Rat Superior Cervical Ganglia: Functional Correlation

Segregation of Acetylcholine and GABA in the Rat Superior Cervical Ganglia: Functional Correlation

GABAergic signaling in the rat pineal gland

γ‐Aminobutyric acid‐containing sympathetic preganglionic neurons in rat thoracic spinal cord send their axons to the superior cervical ganglion

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