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O A Shugurov

Publications and source records attributed to O A Shugurov.

18 recordsLinked to original sources
PubMed1991

[Contribution of antidromic activity, induced by excitation of efferent fibers, to massive potentials of the cat spinal cord].

Biphasic cord dorsum potentials (CDP) were evoked on the cat spinal cord by stimulation of the distal stump of a cut ventral root (V-CDP) or peripheral nerves (N-CDP) with the cord deafferentation in L5-S1 segments. Measurements of their latency and the threshold in the responsible efferent fibres have shown that they were produced mainly by the activity of the low-threshold fibres in the ventral root. Stimulation of peripheral nerves with cord deafferentation has demonstrated a change in the amplitude of the positive presynaptic component of the "standard" CDP. Application of double stimuli on dorsal and ventral inputs has elicited two maxima of V-CDP depression. This depression is connected with developed orthodromic mono- and polysynaptic reflexes in motoneurons. The data obtained confirm that the investigated V-CDP is a component part of the "afferent" spike of standard CDP evoked by stimulation of intact nerves. Such data for main hindlimb nerves of the cat are adduced. A conclusion is drawn that integrity of efferents may be determined by analysis of presynaptic spikes of CDP.

Animals↗
PubMed1988

[The role of homosynaptic depression in stabilizing spinal cord potentials].

A decrease of variation coefficient for the amplitudes of dorsal root potentials and cord dorsum potentials (CDP) was found in anaesthetized spinal cats. Reduction of the number of spikes in neurons, which are suggested to take part in generation of CDP in response to repetitive stimulation of cutaneous nerves was also seen. A maximum decrease of variation coefficient was observed at low frequency of stimulation (0.1-5 Hz). The effects observed can be due to homosynaptic depression.

Animals↗
PubMed1987

[Changes in transmission efficiency in synapses of the dorsal horn of the cat spinal cord during repeated activation of cutaneous afferents].

Inhibition dynamics of certain components of the spinal cord potentials under low frequency stimulation of cutaneous nerves was studied in acute experiments on cats. The experimental data obtained were approximated by the theoretical curve on the assumption that the two-pool model of the transmitter storage was applicable. An increase of the mediator replenishment intensity during rhythmical stimulation has been demonstrated. The results obtained were similar to those obtained from monosynaptic reflex investigations, that demonstrates the likeness of action mechanisms for different afferent synapses.

Afferent Pathways↗
PubMed1982

[Changes in antidromal discharges in the peripheral nerves in the cat in response to polarization of the spinal cord by a steady current].

The influence of constant current passing through the spinal cord cross-section on the antidromic discharges in afferent nerves caused by intraspinal stimulation of central afferent terminals was studied in experiments on anasthetized cats. The current flowing through the spinal cord in the dorso-ventral direction produced an increase or antidromic discharges. The current flowing in the ventro-dorsal direction produced an opposite effect. Facilitation of antidromic discharges evoked by conditioning stimuli decreased with an increase of constant current of both directions. It is suggested that depolarizing shift of the membrane potentials of afferent terminals occurs when the current flows in the dorso-ventral direction. the situation reverses when the direction of current flow becomes opposite.

Animals↗
PubMed1975

[The possibility of different effects of primary afferent depolarization on spinal reflexes].

Intensive depolarization of central primary afferent terminals evoked by strong stimulation of afferent nerves or dorsal root produces recurrent discharges which may be recorded as antidromic dorsal root reflexes. It is shown that the discharges are simultaneously propagating in the dorso-ventral direction and thus produce facilitation of spinal reflexes. The obtained results allow suggesting the existence of two types of influences of the primary afferent depolarization on the reflex transmission to the spinal cord.

Action Potentials↗
PubMedDate not supplied

[A biosynchronization unit for electrophysiologic studies of the brain].

Under registration and accumulation of the spinal cord potentials from the surface of the body, the use was made of biosignals (ECG) which trigger the computerised analysing system. The proposed machine uses ECG as the synchronised signal. The principles of its work and scheme are given as well.

Brain↗