title: Effects of tetracaine on insulin release and calcium handling by rat pancreatic islets.
abstract: The effects of tetracaine on insulin release and 45Ca2+ handling by rat pancreatic islets have been studied under basal (2.8 mM glucose), glucose-stimulated (5.6, 8.3, and 16.7 mM glucose), and 3-isobutyl-1-methylxanthine (IBMX)-stimulated conditions. Islets were isolated by the use of collagenase and used either directly (freshly isolated islets) or after a period under tissue culture conditions. Tetracaine was found to stimulate insulin release under basal conditions, to inhibit glucose-stimulated insulin release, and to potentiate insulin release stimulated by IBMX. In studies on the mechanisms underlying these effects, tetracaine was found to decrease glucose-stimulated net retention of 45Ca2+ (by an action to block the voltage-dependent Ca channels) and to mobilize Ca2+ from intracellular stores. These two actions form the basis for the inhibition of glucose-stimulated insulin release, which depends heavily on Ca2+ entry via the voltage-dependent channels and the synergism with IBMX to potentiate release. No inhibition of IBMX-stimulated release occurs because IBMX does not use the voltage-dependent channels to raise intracellular Ca2+.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004357:Drug Synergism; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013748:Tetracaine / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D007328:Insulin; D013748:Tetracaine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D014700:Verapamil; D005947:Glucose; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine