Inhibitory effects of beta-alanine on the vagal efferent and afferent excitatory responses of the stomach to stimulation of vagal trunk in cats.
The effects of beta-alanine on the electrically evoked vagal efferent (hexamethonium-sensitive initial excitatory response) and afferent (hexamethonium-resistant delayed excitatory response) responses of the cat stomach were studied. beta-alanine (30 to 300 micrograms/kg, i.v.) dose-dependently inhibited both the efferent and afferent response. The IC50 values of beta-alanine on the efferent and afferent response were 296 +/- 65 micrograms/kg and 128 +/- 35 microgram/kg, respectively. Maximal inhibitory effects of beta-alanine (300 micrograms/kg, i.v.) appeared about 1 hr after the injection. Glycine and taurine (100 to 10,000 micrograms/kg) did not affect these responses. Treatment with hexamethonium (10 mg/kg, i.v.) prevented the efferent response, but augmented the afferent response. The treatment with hexamethonium abolished the inhibitory effect of beta-alanine on the afferent response. Both picrotoxin (100 and 500 micrograms/kg, i.v.) and bicuculline (2000 micrograms/kg, i.v.) antagonized the inhibitory effects of beta-alanine on the vagal efferent and afferent responses of the stomach. The present experiments clearly demonstrated that beta-alanine inhibited both the vagal efferent and afferent excitatory responses of stomach to electrical stimulation of vagal trunk in cats.
Pharmacology Division, Kyoto University, Japan.
S
S
Aoki
K
K
Kurahashi
M
M
Iwamoto
A
A
Kawaguchi
H
H
Jino
H
H
Oikawa
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002415:Cats; D004558:Electric Stimulation; D005260:Female; D005998:Glycine / Q000494:pharmacology; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D009476:Neurons, Efferent / Q000187:drug effects* / Q000502:physiology; D010852:Picrotoxin / Q000494:pharmacology; D013270:Stomach / Q000294:innervation* / Q000502:physiology; D013654:Taurine / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects* / Q000502:physiology; D015091:beta-Alanine / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D001640:Bicuculline; D005998:Glycine; D018738:Hexamethonium; D006584:Hexamethonium Compounds; D010852:Picrotoxin; D013654:Taurine; D015091:beta-Alanine; D005680:gamma-Aminobutyric Acid