[Role of ACTH fragments in regulating electrogenesis and electrotonic synaptic interaction of pond snail neurons].

The hypothesis of neuropeptides involvement in intercellular interaction was checked on the neurons VD1 and RPD2 connected with electrotonic synapse with two-way transmission in nerve ganglia of the pond snail. The preparation was perfused with natural and synthetic fragments of ACTH (2 X 10(-7) M). In perfusion with ACTH4-10 solution, synapse became rectified whereas in ACTH4-7 and ACTH5-10 solutions it obtained partially rectified properties. After exposure to ACTH4-7--Pro--Gly--Pro, synapse obtained rectifying properties with one--way increase in conductivity following temporary two-way increase of transmission efficiency. With the use of Pro--Gly--Pro--ACTH4-7--Pro--Gly--Pro, inhibition of the two--way conductivity occurred. Neuropeptides seem to modulate synaptic transmission. Impulse priority depends on the initial level of the cell MPs and is purposefully modulated by the peptides under test.