Jl. Boyer et al., POTENT AGONIST ACTION OF 2-THIOETHER DERIVATIVES OF ADENINE-NUCLEOTIDES AT ADENYLYL CYCLASE-LINKED P-2Y-PURINOCEPTORS, British Journal of Pharmacology, 116(6), 1995, pp. 2611-2616
1 Analogues of adenine nucleotides inhibited beta-adrenoceptor-stimula
ted cyclic AMP accumulation in C6 rat glioma cells with a pharmacologi
cal selectivity consistent with that for involvement of a P-2Y-purinoc
eptor. 2 The inhibitory effect of adenine nucleotides was completely p
revented by pretreatment of cells with pertussis toxin. 3 The capacity
of a series of recently synthesized 2-thioether analogues of adenine
nucleotides to inhibit cyclic AMP accumulation was examined. Several A
TP analogues, e.g. 2-cyclohexylthio and 2-hexylthio ATP, inhibited cyc
lic AMP accumulation with EC(50) values of approximately 30 pM. These
values represent 100,000 fold increases in potency over ATP. 4 Analogu
es of ADP exhibited the same remarkable increase in potency relative t
o their natural congener and diphosphates were at least as potent as t
he corresponding triphosphates at the C6 cell P-2Y-purinoceptor. 5 The
relative potencies of a broad series of agonists at the C6 cell recep
tor did not correspond to the relative potencies of the same compounds
for activation of P-2Y-purinoceptors on turkey erythrocyte membranes.
Some agonists, particularly 2-thioether derivatives were more potent
for stimulation of the C6 cell receptor, whereas other agonists were m
ore potent in the turkey erythrocyte system. 6 These results add furth
er support to the view that the adenylyl cyclase-linked P-2Y-purinocep
tor of C6 rat glioma cells is a different subtype from the phospholipa
se C-linked P-2Y-purinoceptor of turkey erythrocyte membranes and seve
ral mammalian tissues