γ-Aminobutyric acid localization and function as modulator of cholinergic neurotransmission in rat antral mucosal/submucosal fragments

Harty, Richard F.; Boharski, Michael G.; Bochna, Gary S.; Carr, Thomas A.; Eagan, Peter E.; Rings, Matthew; Lassiter, Douglas C.; Pour, M. Parviz; Schafer, Daniel F.; Markin, Rodney S.

doi:10.1016/0016-5085(91)90065-s

Cited by 21 publications

(15 citation statements)

References 24 publications

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“…The present data extend previous work by showing uptake of GABA by both antral and corpus mucosa by a neuronal-type plasma membrane transporter, and by the demonstration of modulation of uptake by the presence of food in the gastric lumen. Harty et al (1991) have shown that GABA increases gastrin release and decreases somatostatin release from antral mucosa by stimulating the secretion of acetylcholine. It is well known that in fasted rats there is a decrease in gastrin release and in the abundance of gastrin mRNA.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies using autoradiography, in situ hybridization and immunocytochemistry, suggest that both cell types are also able to synthesize, transport, store and secrete GABA (Erdo & WolfF, 1988;Jessen, Hills & Limbrick, 1988;Gilon, Tappaz & Remacle, 1991;Davanger, Hjelle, Babaie, Larsson, Hougaard, Storm-Mathisen & Ottersen, 1994). It has been reported that GABA releases acetylcholine from antral mucosal nerve fibres, which in turn stimulates G-cells and inhibits D-cells (Harty, Boharski, Bochna, Carr, Eagan, Rings, Lassiter, Parviz Pour, Schafer & Markin, 1991), but the physiological significance of GABA as a local modulator of antral endocrine function remains uncertain. In the present study we have examined the uptake of [3H]GABA by antral mucosa in vitro: we find enhanced uptake in fasted rats, which could account for known changes in G-cell function on food withdrawal.…”

Section: Introductionmentioning

confidence: 99%

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Physiological regulation of gaba uptake by rat pyloric antral mucosa

Varró

Athanassopolous²,

Dockray³

1996

Experimental Physiology

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physiological regulation of gaba uptake by rat pyloric antral mucosa

Varró

Athanassopolous²,

Dockray³

1996

Experimental Physiology

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“…Recently GABA was localized to nerve fibers within the gastric mucosal and submucosal layers and to epithelial cells of the gastric mucosa, in particular of the antral mucosa [1,[10][11][12][13]. The GABA-immunopositive epithelial cells cannot be seen in the surface epithelium but are confined to the middle and lower parts of the gastric glands and show secretory granules like endocrine cells [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, GABA seems to be synthesized in mucosal and submucosal nerves and epithelial cells of the gastric glands as reflected by the presence of glutamic acid decarboxylase (GAD), the enzyme of GABA synthesis [14,15]. Furthermore GABA can be released from antral mucosal and submucosal tissue slides by a depolarizing stimulus [10,16]. Finally, specific GABA A receptors are localized on epithelial cells of the gastric body and antrum [17].…”

Section: Introductionmentioning

confidence: 99%

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Regulation of Gastrin, Somatostatin and Bombesin Release from the Isolated Rat Stomach by Exogenous and Endogenous Gamma-Aminobutyric Acid

et al. 1998

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Background/Aims and Methods: γ-Aminobutyric acid (GABA) is localized in epithelial cells and intrinsic nerve fibers of the gastric mucosa raising the possibility of a regulatory role for this transmitter. Therefore, it was the aim of the present study to examine the effect of exogenous and endogenous GABA on the neuroendocrine functions of the isolated perfused rat stomach. Results: Infusion of GABA (10^–8, 10^–6, 10^–4 M) caused a significant increase in gastrin release by 187 ± 98, 328 ± 43 and 493 ± 84 pg/20 min and a significant decrease in somatostatin secretion by –540 ± 203, –867 ± 96 and –893 ± 195 pg/20 min, respectively. Release of bombesin-like immunoreactivity (BLI) remained unchanged during infusion of GABA at the concentrations employed. The gastrin and somatostatin responses to 10^–4 M GABA were completely inhibited by the GABA_A antagonist bicuculline (10^–5 M) and the cholinergic blocker atropine (10^–7 M), whereas the GABA_B antagonist CGP 35348 (5 × 10^–5 M) was ineffective. To evaluate the contribution of endogenous GABA in the vagal regulation of gastric neuroendocrine functions, gastrin, somatostatin and BLI responses to electrical stimulation of the vagal nerves were examined in the presence of bicuculline. Vagal stimulation (10 V, 10 Hz, 1 ms) induced a significant inhibition of somatostatin release by –518 ± 78 pg/10 min, which was attenuated to –259 ± 143 pg/10 min (p < 0.05) in the presence of bicuculline. Atropine (10^–7 M) turned vagally induced inhibition of somatostatin release into a stimulation by 928 ± 266 pg/10 min which was not altered by additionally infused bicuculline. Vagally stimulated gastrin release was reduced from 397 ± 47 to 217 ± 72 pg/10 min (p < 0.05) by bicuculline, while atropine had no effect. Vagally induced BLI release was not altered by bicuculline and atropine. Since the effect of bicuculline on vagally induced gastrin release was independent of cholinergic mechanisms, a potential direct effect of GABA on gastrin release was examined in isolated rabbit antral G cells. In this preparation carbachol (10^–4 M) and neuromedin C (10^–9 M) significantly stimulated gastrin release from 2.6 ± 0.4 to 4.9 ± 0.3 and 8.5 ± 0.9% of the total cellular content, respectively, while GABA (10^–10–10^–3 M) changed neither basal nor carbachol- and neuromedin C-stimulated gastrin release. Conclusion: The present data confirm that exogenous GABA stimulates gastrin release and inhibits somatostatin release from the isolated rat stomach via GABA_A receptors by activating cholinergic neurotransmission. Furthermore, it was shown for the first time that endogenous GABA contributes to the vagal regulation of gastrin and somatostatin release from the rat stomach. Inhibition of somatostatin secretion by endogenous GABA is mediated by cholinergic mechanisms, whereas stimulation of gastrin release is mediated by pathways unrelated to the chol...

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Innervation of the gastric mucosa

Ekblad

Mei

Sundler

2000

Microsc. Res. Tech.

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A plethora of neuronal messengers (“classical” transmitters, gaseous messengers, amino acid transmitters, and neuropeptides) are capable of mediating or modulating gastric functions. Accordingly, the stomach is richly innervated. Gastric nerves are either intrinsic to the gastric wall, i.e., they have their cell bodies in the intramural ganglia and thus belong to the enteric nervous system, or they reach the stomach from outside, originating in the brainstem, in sympathetic ganglia, or in sensory ganglia. Topographically, the nerve fibers in the stomach reach all layers from the most superficial portions of the gastric glands to the outer smooth muscle layer. This wide distribution implies that virtually all different cell types may be reached by neuronal messengers. Within the gastric mucosa endocrine and paracrine cells (e.g., gastrin cells, ECL cells, somatostatin cells), exocrine cells (parietal cells, chief cells, mucous cells), smooth muscle cells, and stromal cells are regulated by neuronal messengers. The sensory innervation, responding to capsaicin, plays an important role in mucosal protection, and in ulcer healing. Presumably also other nerves are involved and a plasticity in the neuropeptide expression has been demonstrated at the margin of gastric ulcers. Taken together, available data indicate a complex interplay between hormones, paracrine messengers and neuronal messengers, growth factors and cytokines in the regulation of gastric mucosal activities such as secretion, local blood flow, growth, and restitution after damage. Microsc. Res. Tech. 48:241–257, 2000 © 2000 Wiley‐Liss, Inc.

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γ-Aminobutyric acid localization and function as modulator of cholinergic neurotransmission in rat antral mucosal/submucosal fragments

Cited by 21 publications

References 24 publications

Physiological regulation of gaba uptake by rat pyloric antral mucosa

Physiological regulation of gaba uptake by rat pyloric antral mucosa

Regulation of Gastrin, Somatostatin and Bombesin Release from the Isolated Rat Stomach by Exogenous and Endogenous Gamma-Aminobutyric Acid

Innervation of the gastric mucosa

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