Acetylcholine release in superior cervical ganglia in the guinea pig by the use of tritiated choline
Belluzzi, O.; Simpatico, T.A.; Perri, V.
Bollettino della Societa Italiana di Biologia Sperimentale 58(23): 1570-1576
1982
ISSN/ISBN: 0037-8771 PMID: 7165763 Document Number: 186288
Superior cervical ganglia of guinea pig were stimulated for 30 min at 20 pps in Krebs solution without choline and then incubated in 2 ml medium containing 2 .times. 10-7 M 3H-choline 80 Ci/mM for 20 min at 37.degree. C. After careful rinsing, the ganglia were placed in superfusion chambers, the superfusate was collected in 5 min periods and the outflow of 3H measured in a scintillation counter. Paired ganglia were stimulated twice for 5 min at 1 pps with a 30 min interval in between. Before the 2nd stimulation one of the drugs under study was added to one of the 2 ganglia, whereas the other was kept as control. The ratio of the overflow of tritium obtained by the 2 stimulations S2/S1 was 0.868 .+-. 0.05 (n = 54) for the control. Norepinephrine (1.5 .times. 10-5 M) produced a 73% reduction in the S2/S1 ratio suggesting a strong inhibitory action on ACh determined an increase in S2/S1 ratio greater than 50%, indicating a facilitatory action. Enkephalins showed a dose dependent inhibitory effect with a 25% maximum inhibition, half-maximal inhibition being reached at 5 .times. 10-7 M.