A study of the origin of altered pharmacological reactivity of synaptic structures caused by diabetes and pretreatment with contrainsular agents.

The effect of membrane-stabilizing ganglionic blocking agents was found to be decreased in the ganglia of diabetic cats. Similarly, the sensitivity to membrane-stabilizing muscle relaxants of motor endplates in diabetic rats was also diminished, while the effectivity of depolarizing agents was augmented. Analysing the mechanism of action of these phenomena, it was shown that in diabetes developing as a result of pancreas removal or contrainsular treatment, a factor appeared in the blood of the experimental animals which was heat labile and facilitated the transmission process in the cholinergic synapses. In higher concentration, it produced ganglionic excitation and muscle twitching. This factor influenced the effect of drugs acting at the ganglionc synapses and motor endplates.