Adenosine analogs inhibit acetylcholine release and cyclic AMP synthesis in the guinea-pig superior cervical ganglion.
The ability of adenosine agonists to modulate the electrically evoked release of acetylcholine (ACh) from [3H]choline preloaded guinea-pig superior cervical ganglia (SCG) was investigated. The adenosine A1-receptor selective agonist N6-cyclohexyladenosine (CHA) and 2-chloroadenosine (2-CADO) inhibited the evoked transmitter release, the effect being reversed by the A1-receptor selective antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), and by sulmazole (SUL), which blocks both the A1-receptor and the adenylate cyclase inhibitory regulator Gi. In whole ganglia, CHA decreased both the basal and the forskolin (FSK)-stimulated cyclic AMP synthesis. The latter effect was again prevented by the A1 antagonist DPCPX. These results are compatible with the existence, in the guinea-pig SCG, of adenosine A1-receptors, part of which are located on the presynaptic nerve terminals mediating an inhibition of ACh release.
Borasio
P G
PG
Institute of General Physiology, University of Ferrara, Italy.
Pavan
B
B
Fabbri
E
E
Ginanni-Corradini
F
F
Arcelli
D
D
Poli
A
A
D000109:Acetylcholine / Q000378:metabolism*; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D003864:Depression, Chemical; D004558:Electric Stimulation; D006168:Guinea Pigs; D007093:Imidazoles / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D017783:Superior Cervical Ganglion / Q000187:drug effects / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000502:physiology; D014970:Xanthines / Q000494:pharmacology
D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D014970:Xanthines; D005576:Colforsin; C027513:N(6)-cyclohexyladenosine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000242:Cyclic AMP; C029758:sulmazole; D000241:Adenosine; D000109:Acetylcholine