In Vivo Effects of ?-Bungarotoxin on the Acetylcholine System in Different Brain Areas of the Rat

Publisher Website
Google Scholar
Abstract
The in vivo effects of .beta.-bungarotoxin (.beta.-BT) on the acetylcholine (ACh) system was studied in the whole cerebrum and in different brain regions. The effect of .beta.-BT on cerebral ACh and choline (Ch) contents was time-dependent. A single intracerebroventricular injection of 1 .mu.g toxin increased both the ACh and Ch contents in the cortex, hippocampus and cerebellum, while in the striatum the ACh level was decreased. Ten ng of toxin injected into the lateral ventricle twice, on the 1st and 3rd days, led to a reduced ACh level 2 days after the last treatment. In animals treated with the same dose 3 times, on the 1st, 3rd and 5th days, and sacrificed 2 days after the last injection, the choline acetyltransferase and acetylcholinesterase activities were reduced and the number of muscarinic acetylcholine receptors was decreased. A biphasic effect of the toxin was therefore demonstrated. In the 1st phase of the toxin effect the increased levels of ACh and Ch may be due to the inhibition of neuronal transmission, while in the 2nd phase, when the elements of the ACh system are reduced, the neuronal degenerating effect of .beta.-BT plays a significant role.