Effects of a Dendroaspis neurotoxin on synaptic transmission in the spinal cord and the neuromuscular junction of the frog.
A neurotoxin from the venom of Dendroaspis jamesoni was tested at the neuromuscular junction and at a cholinergic pathway in the isolated spinal cord of the frog. The toxin reduced the amplitude and time constant of decay of miniature endplate currents in the presence of prostigmine, indicating a curare-like action. In the spinal cord it selectively blocked transmission in the cholinergic pathway and increased spontaneous activity. Partial protection against toxin action in the spinal cord was provided by atropine or carbachol. The results suggest that the toxin acts on cholinergic receptors at both sites and also provide further evidence that the pharmacology of the two sites is different.
D000818:Animals; D001001:Anura; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D005071:Evoked Potentials; D066298:In Vitro Techniques; D009045:Motor Endplate; D009469:Neuromuscular Junction / Q000187:drug effects*; D009498:Neurotoxins / Q000494:pharmacology*; D010276:Parasympatholytics / Q000494:pharmacology; D011896:Rana temporaria; D011950:Receptors, Cholinergic / Q000187:drug effects; D012910:Snake Venoms; D013116:Spinal Cord / Q000187:drug effects; D013126:Spinal Nerve Roots / Q000187:drug effects; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects
D009498:Neurotoxins; D010276:Parasympatholytics; D011950:Receptors, Cholinergic; D012910:Snake Venoms; D001285:Atropine; D002217:Carbachol