Comparative study on the sympathomimetic effect of guanethidine and cocaine on rat vas deferens
Patel, M.P.; Shah, D.S.; Batham, A.K.; Rathod, S.P.
Indian Journal of Medical Research 71: 433-437
1980
ISSN/ISBN: 0019-5340 PMID: 7390582 Document Number: 155521
A comparative study of the sympathomimetic effect of guanethidine and cocaine was carried out on isolated vas deferens of rat to differentiate the amine uptake blocking effect of guanethidine from its property to release norepinephrine (NE). Guanethidine (3.38 .times. 10-6 M) showed a neuron blocking and a sympathomimetic effect. The sympathomimetic effect of guanethidine was reduced significantly in reserpinized preparations and in those which were exposed to low temperature (12.degree. C). Equi-effective concentrations of guanethidine (5 .times. 10-5 M) and cocaine (1.24 .times. 10-5 M) for sympathomimetic effect demonstrated that the sympathomimetic effect of guanethidine increased in a time-dependent manner up to a period of 30 min that of cocaine remained the same after 6 min. The sympathomimetic effect of guanethidine is due to a continuous release of NE which reaches peak after 30 min of exposure while cocaine, which blocks only the amino uptake, manifests a sympathomimetic effect which is unaltered from 6-30 min exposure time.