PT  - JOURNAL ARTICLE
AU  - K S Ice
AU  - D W Hay
AU  - W W Fleming
AU  - R L Robinson
AU  - J S Fedan
TI  - Sensitivity changes in the smooth muscle of the guinea-pig isolated vas deferens after treatment of animals with 6-hydroxydopamine.
DP  - 1985 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 349--353
VI  - 235
IP  - 2
4099  - http://jpet.aspetjournals.org/content/235/2/349.short
4100  - http://jpet.aspetjournals.org/content/235/2/349.full
SO  - J Pharmacol Exp Ther1985 Nov 01; 235
AB  - Postjunctional supersensitivity of the smooth muscle of the guinea-pig vas deferens induced by denervation, decentralization and treatment of animals with reserpine has been attributed, in part, to a partial membrane depolarization (8-10 mV) resulting from reduced electrogenic Na+,K+-pumping activity. This study was undertaken to characterize sensitivity changes which occur after treatment of animals with 6-hydroxydopamine (100 mg/kg + 250 mg/kg i.v., 1 day apart). Seven days after the second injection, concentration-response curves for isometric contractile responses to norepinephrine, methoxamine, acetylcholine and histamine were shifted 40.6-, 1.7-, 3.6- and 2.7-fold, respectively, to the left of control; however, the sensitivity to KCl was not increased, which contrasts with the results after denervation, decentralization and reserpine treatment. Ouabain (10(-5) M) produced 1.8- and 1.3-fold leftward shifts of the KCl concentration-response curves in tissues from control and 6-hydroxydopamine-treated animals, respectively. The pronounced effect of ouabain in tissues from treated animals may be an indication that 6-hydroxydopamine treatment does not result in as much inhibition of electrogenic Na+,K+-pumping, and resultant membrane depolarization, as other methods which induce supersensitivity of the guinea-pig vas deferens.