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Study on the possible neurotransmitter of the non-adrenergic non-cholinergic innervation of the rat gastric fundus.
Arch Int Pharmacodyn Ther. 1986 Apr; 280(2 Suppl):110-36.AI

Abstract

The neurotransmitter of the non-adrenergic non-cholinergic inhibitory innervation of the stomach is still unknown. We studied the effect of a series of neurotransmitter candidates, ATP, [Leu]enkephalin and [Met]enkephalin, somatostatin, neurotensin and VIP, in the rat gastric fundus and compared these effects with the response to electrical stimulation of the non-adrenergic non-cholinergic inhibitory neurons. Rats of both sexes were treated with reserpine (5 mg . kg-1 intraperitoneally) 24 h before killing. Longitudinal muscle strips of the gastric fundus were prepared and mounted between parallel platinum electrodes in Krebs solution containing atropine 10(-6) M and serotonin 3.10(-6) M. A maximal relaxatory response was obtained on transmural stimulation of the strips at supramaximal voltage, 1 msec and 5 Hz. ATP (10(-6)-10(-3) M) elicited a biphasic response, a small relaxation followed by a contraction. The maximal relaxatory response induced by ATP was much lower than that induced by transmural stimulation during 45 sec (37.3% versus 166.2%, where 100% is the maximal contractile response to ATP, n = 17). Desensitization to ATP did not influence the relaxation induced by transmural stimulation. [Met]enkephalin, [Leu]enkephalin and naloxone did not change the tone of the strips or the amplitude of the electrically induced relaxation. Somatostatin had no influence while neurotensin induced a concentration-dependent contraction from 10(-9) M or 10(-8) M on. VIP (10(-10)-3.10(-8) M) induced a concentration-dependent relaxation. The maximal relaxation induced by VIP was 120.8% of that induced by transmural stimulation (n = 16). The relaxation induced by VIP 10(-8) M, left in contact with the tissue for 10 min, was comparable to that induced by transmural stimulation during 10 min, except for a lag time of more than 10 sec after the addition of VIP. The relaxation induced by VIP was not influenced by tetrodotoxin, phentolamine or propranolol. The peptidase trypsin (10(-6) M) antagonized the relaxation by exogenously added VIP but did not influence the electrically induced relaxation. The results obtained in this study show that, of the substances tested, only VIP mimics the relaxation induced by stimulation of the inhibitory non-adrenergic non-cholinergic neurons in the rat gastric fundus; VIP therefore seems a reasonable candidate as neurotransmitter of these neurons.

Authors

No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

2873800

Citation

Lefebvre, R A.. "Study On the Possible Neurotransmitter of the Non-adrenergic Non-cholinergic Innervation of the Rat Gastric Fundus." Archives Internationales De Pharmacodynamie Et De Therapie, vol. 280, no. 2 Suppl, 1986, pp. 110-36.
Lefebvre RA. Study on the possible neurotransmitter of the non-adrenergic non-cholinergic innervation of the rat gastric fundus. Arch Int Pharmacodyn Ther. 1986;280(2 Suppl):110-36.
Lefebvre, R. A. (1986). Study on the possible neurotransmitter of the non-adrenergic non-cholinergic innervation of the rat gastric fundus. Archives Internationales De Pharmacodynamie Et De Therapie, 280(2 Suppl), 110-36.
Lefebvre RA. Study On the Possible Neurotransmitter of the Non-adrenergic Non-cholinergic Innervation of the Rat Gastric Fundus. Arch Int Pharmacodyn Ther. 1986;280(2 Suppl):110-36. PubMed PMID: 2873800.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Study on the possible neurotransmitter of the non-adrenergic non-cholinergic innervation of the rat gastric fundus. A1 - Lefebvre,R A, PY - 1986/4/1/pubmed PY - 1986/4/1/medline PY - 1986/4/1/entrez SP - 110 EP - 36 JF - Archives internationales de pharmacodynamie et de therapie JO - Arch Int Pharmacodyn Ther VL - 280 IS - 2 Suppl N2 - The neurotransmitter of the non-adrenergic non-cholinergic inhibitory innervation of the stomach is still unknown. We studied the effect of a series of neurotransmitter candidates, ATP, [Leu]enkephalin and [Met]enkephalin, somatostatin, neurotensin and VIP, in the rat gastric fundus and compared these effects with the response to electrical stimulation of the non-adrenergic non-cholinergic inhibitory neurons. Rats of both sexes were treated with reserpine (5 mg . kg-1 intraperitoneally) 24 h before killing. Longitudinal muscle strips of the gastric fundus were prepared and mounted between parallel platinum electrodes in Krebs solution containing atropine 10(-6) M and serotonin 3.10(-6) M. A maximal relaxatory response was obtained on transmural stimulation of the strips at supramaximal voltage, 1 msec and 5 Hz. ATP (10(-6)-10(-3) M) elicited a biphasic response, a small relaxation followed by a contraction. The maximal relaxatory response induced by ATP was much lower than that induced by transmural stimulation during 45 sec (37.3% versus 166.2%, where 100% is the maximal contractile response to ATP, n = 17). Desensitization to ATP did not influence the relaxation induced by transmural stimulation. [Met]enkephalin, [Leu]enkephalin and naloxone did not change the tone of the strips or the amplitude of the electrically induced relaxation. Somatostatin had no influence while neurotensin induced a concentration-dependent contraction from 10(-9) M or 10(-8) M on. VIP (10(-10)-3.10(-8) M) induced a concentration-dependent relaxation. The maximal relaxation induced by VIP was 120.8% of that induced by transmural stimulation (n = 16). The relaxation induced by VIP 10(-8) M, left in contact with the tissue for 10 min, was comparable to that induced by transmural stimulation during 10 min, except for a lag time of more than 10 sec after the addition of VIP. The relaxation induced by VIP was not influenced by tetrodotoxin, phentolamine or propranolol. The peptidase trypsin (10(-6) M) antagonized the relaxation by exogenously added VIP but did not influence the electrically induced relaxation. The results obtained in this study show that, of the substances tested, only VIP mimics the relaxation induced by stimulation of the inhibitory non-adrenergic non-cholinergic neurons in the rat gastric fundus; VIP therefore seems a reasonable candidate as neurotransmitter of these neurons. SN - 0003-9780 UR - https://www.unboundmedicine.com/medline/citation/2873800/Study_on_the_possible_neurotransmitter_of_the_non_adrenergic_non_cholinergic_innervation_of_the_rat_gastric_fundus_ DB - PRIME DP - Unbound Medicine ER -