Modification of mouse islet function by 5-hydroxytryptamine, dopamine and their precursors.
5-Hydroxytryptamine (5-HT) and dopamine were found to inhibit glucose-induced insulin release and 45Ca2+ net uptake in islets microdissected from ob/ob-mice. Dopamine was more potent than 5-HT. L-DOPA, the precursor of dopamine, had an effect similar to that of dopamine and this effect was reduced by benserazide. L-5-hydroxytryptophan, the precursor of 5-HT, potentiated glucose-induced insulin release and stimulated 45Ca2+ uptake. This effect was also blocked by benserazide. It is concluded that dopamine is a stronger inhibitor than 5-HT and that the different actions of 5-HTP and L-DOPA might be explained by this difference in the magnitude of inhibition.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D001545:Benserazide / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D004298:Dopamine / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D007980:Levodopa / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*
D007328:Insulin; D012701:Serotonin; D007980:Levodopa; D001545:Benserazide; D006916:5-Hydroxytryptophan; D005947:Glucose; D002118:Calcium; D004298:Dopamine