Role of cyclic AMP in stimulation-evoked release of 3H-noradrenaline from rabbit isolated ear artery
Abrahamsen, J.; Nedergaard, O.A.
Pharmacology and Toxicology 76(3): 185-189
1995
ISSN/ISBN: 0901-9928
PMID: 7617543
Accession: 009366222
The possible involvement of cyclic AMP in the stimulation-evoked 3H-overflow from rabbit isolated ear artery preloaded with 3H-noradrenaline was studied. Cyclic AMP (10-5-3 times 10-4M), 8-bromo-cyclic AMP (3 times 10-4M) and adenosine (10-5-3 times 10-4M) enhanced stimulation-evoked 3H-overflow. Dibutyryl-cyclic AMP (10-5-3 times 10-4M) had no effect. Theophylline (3 times 10-5M) and the phosphodiesterase inhibitor AH 21-132 (3 times 10-5M) did not alter the enhancement of 3H-overflow caused by either cyclic AMP or adenosine. Forskolin (3 times 10-6M) and the phosphodiesterase inhibitors ICI 63 197 (10-4M) and AH 21-132 (3 times 10-6-3 times 10-5M) increased stimulation-evoked 3H-overflow. Forskolin (10-6M) enhanced the effect of ICI 63 197 (3 times 10-5M) but it did not alter the effect of AH 21-132. It is concluded that cyclic AMP is involved in the stimulation-evoked release of noradrenaline from postganglionic sympathetic nerves in the rabbit ear artery.