Original Articles
Copyright ©The Author(s) 1998. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 15, 1998; 4(5): 426-429
Published online Oct 15, 1998. doi: 10.3748/wjg.v4.i5.426
Modulation of hypothalamic arcuate nucleus on gastric motility in rats
Guang-Yao Xu, Rong Ma, Qi Cao, Bao-Tian Su
Guang-Yao Xu, Rong Ma, Qi Cao, Department of Physiology, Anhui Medical University, Hefei 230032, Anhui Province, China
Bao-Tian Su, Department of Pathophysiology, Anhui Medical University, Hefei 230032, Anhui Province, China
Guang-Yao Xu, male, born on 1927-12-27 in Xianju County, Zhejian Province, China, graduated in 1952 from Shanghai Medical University, now professor of physiology of Anhui Medicial University, having 100 papers and two books published.
Author contributions: All authors contributed equally to the work.
Correspondence to: Prof Guang-Yao Xu, Department of Physiology, Anhui Medical University, No.69 Meishan Road, Hefei 230032, Anhui Province, China
Telephone: +86-551-3651751
Received: March 26, 1998
Revised: May 13, 1998
Accepted: July 6, 1998
Published online: October 15, 1998
Abstract

AIM: To investigate whether the arcuate nucleus (ARC) could modulate gastric motility, and if so, what are the mechanisms or pathways.

METHODS: Wistar rats, anaesthetized with urethan, parameters of stimulation and electrolytic lesion sites were determined according to the Paxinos and Watson “ATLAS of rat brain in steriotaxic coordinate”. Intragastric pressure ( IGP ) and gastric motility were measured by Reybould¡äs method.

RESULTS: Electrical stimulation of ARC could obviously decrease the IGP by 42.2% ± 5.4%, n = 15, P < 0.01, and the phasic gastric contractions disappeared. The analysis showed that the locus coeruleus (LC) and dorsal raphe (DR) nuclei may be involved in central, but without the invovement of β-endorphinergic neurons rich in the ARC, while in periphery, the peripheral neural pathways are both vagus and sympathetic nerves. The fibers in vagus may be non-cholinergic. Humoral factors may also be involved. At the receptor level, Tonic action of adrenergic nerve in the stomach is mainly inhibitory; β-receptors, which may be present on the stomach wall and mediate inhibition; and α-receptors, which come into play through vagus, mediate inhibition, but those present on the smooth muscle mediate sympathetic excitation. Microinjection of TRH into ARC could significantly increase the IGP by 183.02% (0.53 kPa ± 0.08 kPa vs 1.5 kPa ± 0.6 kPa, n = 10, P < 0.001), the rate and amplitude of phasic gastric contraction were also increased (3 cpm vs 6 cpm-8 cpm). The peripheral pathway of such excitatory effects were transmitted with cholinergic vagus nerve mediated by M-receptor.

CONCLUSION: ARC could modulate gastric motility biphasically, inhibitory and excitatory, depending on the nature of stimuli.

Keywords: headings gastric motility; arcuate nucleus; neural pathways; vagus nerve; sympathetic nerve; electrical stimulation