Basic formulations of the quantum theory for synaptic transmission are listed Methods for determining the mean quantum content, quantum value and binomial parameters describing the amplitude distributions of the unitary and "minimal" postsynaptic potentials are discussed Literature and author's determinations of the quantum parameters for the synapses of the central nervous system are described The comparison is made with similar determinations for more studied peripheral junctions Some difficulties and perspective of the quantum theory are discussed

Quantum analysis of postsynaptic potentials

Parameters of IPSPs and characteristics of inhibitory neuromuscular transmission in the dactylopodite-opener muscle of the crayfish pincer at various rhythms of activity were studied by intracellular recording. The presynaptic conduction nature of high-frequency (pessimal) blockade of the inhibitory system was demonstrated. Transformation of the rhythm of stimulation correlated with a decrease in conduction velocity along the inhibitory axon and (or) its branches. At high frequencies of stimulation the mean quantum composition of IPSPs of the potentiation plateau before the beginning of rhythm transformation was lower than at lower frequencies. No signs of exhaustion of mediator reserves were found in the course of high-frequency activity. It is concluded that the mechanism of secretion of inhibitory mediator is more reliable than the function of conduction of the presynaptic nervous impulse. The possible functional significance of the comparatively low reliability of function of crustacean nerve fibers is discussed.

Drabkina Tm

Papers

Evaluation of the quantum content of excitatory postsynaptic potentials in neuromuscular synapses of a complex type