Effect of cocaine on tritium overflow evoked from vasa deferentia previously loaded with [3H]noradrenaline by stimulation using different types of electrode.
In mouse and guinea-pig vasa deferentia previously incubated with [3H]noradrenaline, electrical stimulation applied through parallel electrodes (transmurally) increased overflow of tritium 2- to 5-fold above the resting value. Electrical stimulation applied using methods involving more substantial conduction of nerve impulses in neuronal elements in the tissues evoked a tritium overflow which was smaller (70%) than that evoked by transmural stimulation. Cinchocaine (25 microM), tetrodotoxin (0.5 microM) or the absence of calcium effectively abolished evoked overflow in both tissues whichever method of stimulation was used. In mouse vas deferens, cocaine (10 microM) did not alter overflow evoked by either transmural or axonal stimulation while 100 microM produced a reduction. In guinea-pig vas deferens, cocaine (10 microM) produced a statistically significant increase in evoked overflow of about 50% or more with both transmural and axonal stimulation. As in mouse vas deferens, 100 microM cocaine produced a reduction. It is concluded that the action of cocaine is independent of these methods of stimulation and that some difference in the arrangement of the noradrenergic nerves in the two species may account for the differential effect of cocaine observed.
Department of Pharmacology, University of Leeds, Yorkshire, UK.
A M
AM
Bedwell
M
M
el-Mas
I E
IE
Hughes
D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D004558:Electric Stimulation; D004566:Electrodes; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism*; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism
D003042:Cocaine; D009638:Norepinephrine