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Biomedical subjects

V L Zhuravlev

Publications and source records attributed to V L Zhuravlev.

26 records · Page 2Linked to original sources
PubMed1975

[Electrical characteristics of the sensory neurons of the medical leech].

The electrical characteristics of three types of sensory neurons (N, T and P) were determined in the leech Hirudo medicinalis. Statistically significant differences were found between the values of tau, Cs and Rs in the neurons of N- and T-types. The same parameters show the least variation coefficients. The value of time constant (tau) is 17.000-46 ms, the resistivity of the soma membrane TRs) is 19.50 kphi-cm2 in T-neurons and 35 kphi-cm2 in N-neurons. The surface of the neurons estimated by their capacitance (Cs) can be 4-10 times larger than the surface of a sphere of the same size. The possible influence of electrical characteristics of the neurons on the peculiarities of their electrical reactions is discussed.

Action Potentials↗
PubMedDate not supplied

Viscerocardiac reflexes of the snail.

The viscerocardiac and cardiocardiac reflexes in the snail are effectuated by just two inhibitory motoneurons of the visceral ganglion. The neurons are switched on in parallel and have extensive, partially overlapping receptive fields. Due to the high degree of sensitivity of the nerve endings of these cells to mechanical stimuli, the inhibitory motoneurons of the heart perform an afferent function at the same time. A morphological analysis of the inhibitory neurons demonstrated their identity to the previously identified V21 multimodal interneuron.

Animals↗
PubMedDate not supplied

[Viscero-cardiac reflexes in the edible snail].

Only two inhibitory neurons in the visceral ganglia provide the viscero-cardial and cardio-cardial reflexes of Helix pomatia. These neurons are connected in parallel and do not interact with each other. The cells have extensive receptive fields in all visceral organs which are considerably overlapped. These inhibitory neurons can provide the afferent function because of a high sensitivity to tactile stimulation of their endings. The analysis of the data showed that morphological and functional characteristics of the neurons in question corresponded completely to previously identified multifunctional interneuron V21.

Animals↗
PubMedDate not supplied

[Postsynaptic potentials in the myocardium of snails in the genus Helix].

Cardioregulating neurones in the right parietal and visceral ganglia of the snail evoke postsynaptic potentials of various duration, amplitude and polarity in the auricular and ventricular myocardium. Inhibitory neurones with a marked background activity (1-2 imp/s) evoke IPSPs with a duration of 150-200 msec and a latent period of 160-220 msec in the auricle, these potentials being blocked by tubocurarine. EPSPs of approximately the same duration may be recorded in the ventricle during stimulation of the commanding neurones of the pneumostome LPa3 and PPa/3, as well as unidentified neurones. Action potentials in some other identified cardiostimulating neurones (PPa7, V1, V6) induce slow and sustained depolarization in the myocardium. Functional specificity of elements within fast and slow regulatory systems is suggested: discrete IPSPs and EPSPs account mainly for coordination of the systolic contractions of the auricle and ventricle, whereas long-lasting PSPs affect the frequency and intensity of the whole heart.

Animals↗
PubMedDate not supplied

[Alteration of the electrophysiologic characteristics of the neurons of the great pseudo-equine leech after increasing the intracellular concentration of sodium ions].

Changes of membrane potential (MP), amplitude of action potential (AAP) and continuence of AP (CAP) of identified neurons of leech Haemopis sanguisuga have been investigated at high intracellular Na+ concentration. It has been shown that a moderate increase of intracellular Na+ concentration leads to hyperpolarization of the membrane to 15 mV and a certain increase of AAP and CAP. A further increase of [Na+]in leads to a sharp decrease of AAP and small decrease of CAP. Possible mechanisms of the phenomena described are discussed.

Action Potentials↗