Characterization of the effects of neurokinins on canine antral muscle

Journal Article · Thu Dec 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6036894

Koelbel, C B; Mayer, E A; Van Deventer, G; Snape, Jr, W J; Patel, A ^[1]

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1. Harbor-UCLA Medical Center, Torrance, CA (USA) Wadsworth Hospital, Los Angeles, CA (USA)

The excitation of longitudinal antral muscle by substance P (SP) involves both a myogenic and a cholinergic effect. To examine if these responses are mediated by different neurokinin receptors, the authors studied the mechanical response and the release of ({sup 3}H)acetylcholine from antral muscle strips in response to SP, substance P methylester (SPME), neurokinin A (NKA), neurokinin B (NKB), and several nonmammalian tachykinins. All peptides studied showed a dose-dependent inotropic and chronotropic effect on spontaneous phasic contractions. This ionotropic effect in longitudinal muscle was partially atropine sensitive for SPME, SP, and NKB but not for NKA, whereas neither atropine nor tetrodotoxin had an effect in circular muscle. In longitudinal muscle, all three neurokinins were equipotent. In longitudinal muscle treated with atropine and in circular muscle, the rank order of potency for the inotropic response was NKA > NKB > SP > SPME. For the chronotropic response the rank order was SPME, SP > NKA > NKB. NKA, NKB, and SP caused a dose-dependent, tetrodotoxin-sensitive increase in ({sup 3}H)acetylcholine release from strips preincubated with ({sup 3}H)choline. NKA was significantly more potent to release ({sup 3}H)acetylcholine than either NKB or SP. The stimulated release was inhibited by (D-Ala{sup 2},D-Met{sup 5})methionine enkephalinamide and the SP antagonist, spantide. These results are consistent with the hypothesis that NKA is the natural ligand mediating the myogenic inotropic response in both muscle layers and the cholinergic response in longitudinal muscle.

• OSTI ID: 6036894
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:6; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
ALKALOIDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
ATROPINE
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
DOGS
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ESTERS
HYDROGEN COMPOUNDS
KININS
MAMMALS
MUSCLES
NEUROREGULATORS
ORGANIC COMPOUNDS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PEPTIDES
PHYSIOLOGY
POLYPEPTIDES
PROTEINS
QUATERNARY COMPOUNDS
TRITIUM COMPOUNDS
VERTEBRATES