[Input-output characteristics of the motor neuron pool during strychninization in dogs of various ages, (an electrophysiological analysis of the occurrence of inhibitory interneurons in postnatal ontogeny)].

In connection with data on the absence of spinal forms of reciprocal inhibition in ante natal and early postnatal periods in puppies, it was decided to use strychninization as a physiological tool which enables to evaluate the onset of the activity of the inhibitory interneurones which are involved into realization of postsynaptic inhibition. Experiments were made on puppies from three age groups (up to 5 days 8--10 days and 20--30 days) in which mono- and polysynaptic reactions to afferent stimulation were recorded. It was established that the onset of the activity of inhibitory interneurones in the developing neuronal system takes place after realization of antigravitational reactions. At the age of 10--30 days, block of postsynaptic inhibition by strychnine returns the spinal cord to that type of reactions which are typical of antenatal and early postnatal periods.