A neurokinin-1 receptor antagonist reduced hypersalivation  and gastric contractility related to emesis in dogs

The roles of tachykinin neurokinin-1 (NK1) receptors in the induction of fictive retching, hypersalivation, and gastric responses associated with emesis induced by abdominal vagal stimulation were studied in paralyzed, decerebrated dogs. Vagal stimulation induced gradual increases in salivary secretion and activity of the parasympathetic postganglionic fibers to the submandibular gland, relaxation of the gastric corpus and antrum, and fictive retching. However, hypersalivation and increased nerve activity were suppressed and antral contractility was enhanced during fictive retching. An NK1 receptor antagonist, GR-205171, abolished the enhancement of antral contractility and fictive retching but had no effect on corpus and antral relaxation. Hypersalivation and increased nerve activity were inhibited by GR-205171 but were not completely abolished. Reflex salivation by lingual nerve stimulation was unaffected. These results suggest that GR-205171 acts on the afferent pathway in the bulb and diminishes hypersalivation and antral contraction related to emesis as well as fictive retching but does not affect gastric relaxation or hypersalivation induced by the vagovagal, vagosalivary, and linguosalivary reflexes.

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Salivary secretion in cat submandibular gland mediated by chorda tympani afferents

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.268.2.r438 ◽

1995 ◽

Vol 268 (2) ◽

pp. R438-R444 ◽

Cited By ~ 7

Author(s):

H. Izumi ◽

K. Karita

Keyword(s):

Submandibular Gland ◽

Salivary Secretion ◽

Lingual Nerve ◽

Prior Treatment ◽

Chorda Tympani ◽

Chorda Tympani Nerve ◽

Autonomic Ganglion ◽

Blood Flow Increase ◽

A Site ◽

Stimulation Of

The aim of the present study was to investigate whether the afferent traffic from the tongue mediated only via the chorda tympani nerve (CTN) can still elicit reflex salivary and vasodilator responses in the cat submandibular gland (SMG) after section of the lingual nerve proper (LNP). Electrical stimulation of the chorda lingual nerve (CLN) at a site approximately 5 mm distal to the intersection of the CLN and the SMG duct elicited salivary and vasodilator responses in the SMG in sympathectomized cats. Both responses were unaffected by section of the LNP. The optimal frequency of CLN stimulation for submandibular salivation and vasodilation was 20 Hz, regardless of whether the LNP had been cut. Prior treatment with the autonomic ganglion blocker hexamethonium (10 mg/kg iv) virtually abolished the salivation and the blood flow increase in SMG. Prior treatment with scopolamine (0.1 mg/kg iv) almost abolished the salivary secretions but had no effect on the vasodilator responses in the SMG elicited by CLN stimulation after LNP section. The mechanism underlying the reflex submandibular salivation mediated by chorda tympani afferents appears to involve parasympathetic muscarinic receptors, but the mechanism for the vasodilator response has yet to be established. These results indicate that afferent traffic passing through the CTN on CLN stimulation is importantly involved in the parasympathetic reflex secretory and vasodilator responses in the cat SMG.

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