Striatal dopamine release in vitro: a beta-adrenoceptor-regulated response not mediated through cyclic AMP.
The effects of (-)isoproterenol (10(-6) M), dibutyryl cyclic AMP (10(-3) M), and the phosphodiesterase inhibitor 3-isobutyl-l-methylxanthine (IBMX) (10(-4) M) on in vitro [3H]dopamine ([3H]DA) efflux and synthesis were studied in rat striatal slices continuously superfused with [3H]tyrosine. The beta-adrenoceptor agonist (-)isoproterenol induced an immediate and significant facilitation of [3H]DA efflux but did not alter [3H]DA synthesis as measured by [3H]H2O formation. In contrast, both dibutyryl cyclic AMP and IBMX enhanced [3H]DA synthesis as well as efflux. The presence of IBMX in the superfusing medium did not potentiate the augmentation of [3H]DA efflux caused by (-)isoproterenol. Additionally, the blockade of [3H]DA synthesis by alpha-methyl-p-tyrosine (10(-4) M) completely prevented the action of dibutyryl cyclic AMP on [3H]DA efflux. However, under similar conditions, (-)isoproterenol was still able to increase [3H]DA efflux. The results suggest that (-)isoproterenol can modify striatal DA release through a mechanism not involving cyclic AMP.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D003342:Corpus Striatum / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D004298:Dopamine / Q000096:biosynthesis / Q000378:metabolism*; D004357:Drug Synergism; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D003994:Bucladesine; D000242:Cyclic AMP; D007545:Isoproterenol; D015056:1-Methyl-3-isobutylxanthine; D004298:Dopamine