Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
GASTROESOPHAGEAL AFFERENT AND SEROTONERGIC INPUTS TO VAGAL EFFERENT NEURONS
Autore:
BLACKSHAW LA;
Indirizzi:
ROYAL ADELAIDE HOSP,GASTROENTEROL UNIT ADELAIDE SA 5000 AUSTRALIA
Titolo Testata:
Journal of the autonomic nervous system
fascicolo: 2, volume: 49, anno: 1994,
pagine: 93 - 103
SICI:
0165-1838(1994)49:2<93:GAASIT>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
UPPER GASTROINTESTINAL-TRACT; ANESTHETIZED FERRET; RECOGNITION SITES; FIBER DISCHARGE; BRAIN-STEM; MECHANORECEPTORS; RECEPTORS; 5-HYDROXYTRYPTAMINE; RAT; CHEMORECEPTORS;
Keywords:
FERRET; ESOPHAGUS; STOMACH, 5-HT RECEPTOR; VAGUS NERVE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
L.A. Blackshaw, "GASTROESOPHAGEAL AFFERENT AND SEROTONERGIC INPUTS TO VAGAL EFFERENT NEURONS", Journal of the autonomic nervous system, 49(2), 1994, pp. 93-103

Abstract

Peripheral 5-HT3 receptor mechanisms are involved in activation of gastrointestinal (GI) mucosal vagal afferent fibres. 5-HT3 receptor mechanisms in the central nervous system (CNS) may be involved in behavioural and reflex motility responses. This study investigates the processing of different sensory inputs in the CNS and the involvement of 5-HT3 receptors at these different levels. In Urethane (1.5 g/kg, i.p.) anaesthetized, splanchnectomized ferrets, the jugular vein was cannulated for intravenous (i.v.) drug injection, and the coeliac axis for intraarterial (i.a.) injection close to the upper GI tract. The carotid artery was intubated with a T-cannula for CNS-directed intracarotid (i.c.) injections. An intragastric cannula was used for fluid distension (40-50 ml), and an oesophageal catheter for balloon distension (2 ml). Efferent fibres were dissected from the right cervical vagus for single-unit recording. Nineteen single vagal efferent fibres were selected,with low frequency resting discharge (2.5 +/- 0.3 impulses/s), but norespiratory or cardiovascular phasic input. All responded rapidly (< 2.5 s) to gastric distension (532 +/- 230% change in firing rate) and oesophageal distension (300 +/- 170%). Gastric distension caused excitation in 14 fibres, inhibition in 4 fibres, and a biphasic response in1. Oesophageal distension excited 16 and inhibited 3. Discharge was also influenced by i.a. injection of 5-HT or the 5-HT3 receptor agonist2-methyl 5-HT (10-100 mu g) in all fibres tested. These responses consisted of rapid (< 2.5 s) and powerful changes in firing rate, with excitation, inhibition or biphasic responses. 65% of responses to i.c. or i.v. injection were opposite in direction to those after dose i.a. injection, indicating the activation of a different population of receptors. No differences were seen between effects of i.c. and i.v. injections. The 5-HT3 receptor antagonist granisetron (100 mu g/kg, i.v.) blocked or reduced efferent responses to 5-HT receptor agonists, whereasresponses to gastric and oesophageal distension were unchanged. Thus there is extensive convergence of inputs from gastric and oesophageal mechanoreceptors onto vagal motorneurones. These central effects of mechanical stimuli do not involve 5-HT3 receptor mechanisms. Other 5-HT3receptor inputs are evident, probably peripherally from GI mucosal afferent fibres and from within the CNS.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/09/20 alle ore 23:34:17