Biomedical subjects

O I Tsaturian

Publications and source records attributed to O I Tsaturian.

2 recordsLinked to original sources

PubMedDate not supplied

[Selective decrease in neuron excitability during habituation].

By means of the intracellular recording a study was made of the habituation to tactile stimuli in Helex pomatia neurones and of the influence of acetylcholine (ACh) microionphoresis on the response to a habituating stimulus in those units which before habituation reduced the reaction to a tactile stimulus under the action of ACh. Habituation was attended with a diminution of EPSP and of the action potential (AP) elicited by the habituating stimulus. The AP generation threshold and the probability of AP blockade increased with stimuli repetition. An extra stimulus produced in the neurones a greater AP at a lower threshold. After habituation elaboration, Ach increased the neurone response to the habituating stimulus: EPSP and the probability of AP generation increased, while the AP threshold was lowered. At the interaction of the activated synapses with the neurone, the electrogenic and chemical properties of its membrane may probably change for a short time so that the threshold and the AP and EPSP amplitude may differ for the stimuli with different biological significance.

Acetylcholine↗

PubMedDate not supplied

[Divergent effect of acetylcholine on processes of habituation and disinhibition].

The elaboration of habituation to repeated tactile stimuli was studied in snail (Helix pomatia) by means of intracellular recording of the neuronal activity and microionophoresis of acetylcholine (ACh). Light or a stronger tactile stimulation served as extrastimulus. The elaboration of habituation was accompanied by a rise in the threshold of action potentials (APs) generation, evoked by the habitual stimulus, and by a lowering of the threshold of APs elicited by the extrastimulus. Prior to the habituation neuronal responses to tactile or photic stimuli did not change against the ACh background. After habituation was elaborated the ACh administration led to disinhibition of responses to the habitual stimulus (in particular, the AP threshold became lower), and to a decrease in responses to the extrastimulus (AP threshold rose). It is assumed that hibituation changes the chemical responses caused in the neurone by the activation of both the pool of synapses, corresponding to the habitual stimulus, and the pool of synapses corresponding to the extrastimulus. These changes, however, are of a qualitatively different character.

Acetylcholine↗