C. Allgaier et al., P-2 PURINOCEPTORS MODULATING NORADRENALINE RELEASE FROM SYMPATHETIC NEURONS IN CULTURE, European journal of pharmacology, 252(2), 1994, pp. 180000007-180000008
ATP (1 mM) inhibited, whereas 2-methylthio-ATP (30 mu M), a P-2Y-selec
tive purinoceptor agonist, increased electrically evoked release of [H
-3]noradrenaline from chick sympathetic neurons. The P-2X-selective pu
rinoceptor agonist alpha,beta-methylene-ATP (30 mu M) had no effect. T
he ATP-induced inhibition of release as well as the facilitation cause
d by 2-methylthio-ATP was not affected by the selective adenosine (P-1
) receptor antagonist 8-(p-sulfophenyl)-theophylline (8-PST; 100 mu M)
, but completely prevented by the non-selective P-2 antagonist suramin
(300 mu M). The present data reveal a dual regulation of noradrenalin
e release from sympathetic neurons. Facilitation seems to be mediated
by a P-2Y purinoceptor, whereas inhibition is caused by a P-2 purinoce
ptor which needs further subtype characterization.