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Biomedical subjects

R A Durinian

Publications and source records attributed to R A Durinian.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Role of the substantia grisea centralis of the rat brain in regulating pain sensitivity during auricular electrostimulation].

The effect of central gray (CG) on analgesia produced by auricular electrostimulation (AES) has been studied on rats. In the animals with removed CG, the latent periods (LP) of pain responses measured after AES by the hotplate and tail-flick tests were significantly shorter than those in the control group. In the animals with removed CG, the LP measured by the hot-plate test before stimulation was significantly longer as compared to the control. The initial magnitude of the LP measured by the tail-flick test did not differ from the same indicators in the control group rats.

Animals↗
PubMed1981

[Reflex suppression of evoked nociceptive responses in the parafascicular complex and posterior ventromedial nucleus of the thalamus in cats during electroacupuncture].

Acute experiments on cats have shown that electroacupuncture (EA) of auricular points inhibits the amplitude of evoked potentials (EP) induced by noxious stimulation of the tooth pulp in the parafascicular complex and the posterior ventromedial nucleus of the thalamus. The amplitude of evoked potentials in the parafascicular complex was inhibited by 70% of the control level, the effect lasting 40--50 min and being recovered by the control level in the next 50 min. The amplitude of evoked potentials in the posterior ventromedial nucleus of the thalamus was inhibited by 50% of the control level, the effect lasting 30 min, followed by the recovery to the control level in the next 20--30 min. The amplitude of EP induced by tactile stimulation of the mouth lip was not appreciably affected by EA. It is suggested that varying degrees of the inhibition of evoked nociceptive responses in specific and non-specific areas of the thalamus are determined by the features of functional organization of the afferent inputs.

Acupuncture Therapy↗
PubMed1980

[Electroacupuncture inhibition of nociceptive responses in the caudal trigeminal nucleus].

Acute experiments on cats showed that auricular electroacupuncture (AEAP)) produces significant inhibition of evoked potentials (EP) in the caudal trigeminal nucleus which occur under single stimulation of the tooth pulp. The inhibition of EP lasts for 60--80 min. Then gradual (over 30--40 min) recovery of EP is recorded. Acupuncture stimulation decreases insignificantly the amplitude of EP caused by irritation of mouth mucosa. This fact indicates that AEAP inhibits nociceptive responses but does not affect mediation of signals in other modalities. It was established that reacing of AEAP analgetic effect does not require that the classical scheme of acupuncture point localization be strictly followed.

Acupuncture Therapy↗
PubMed1980

[Representation of afferent nerves from the concha auriioulae in the caudal nucleus of the trigeminal system].

It was shown in acute experiments cn cats that the auricular trigeminal nerve consists of A8 group fibers. Threshold electric stimulation of the nerve activates the fibers of the dorsal and ventral trigeminal tracks and neurons of the caudate nucleus at the level 3 mm caudal to the obex. Neuronal units of paramedian and lateral reticular nuclei can be activated by electric stimulation of the fibers of the auricular trigeminal nerve that is adequate to both noxious and non-noxious types of stimulation.

Animals↗
PubMed1977

[Relationship between a state of sleep and wakefulness and transmission of an afferent signal through the posterior ventral nucleus of the thalamus].

Chronic experiments were carried out on nonanesthetized cats. A study was made of peculiarities attending the transmission of the afferent signals and the following inhibitory processes in the posterior ventral nucleus of the thalamus, depending on the state of sleep and wakefulness. Transmission of the signals decreases during the dreaming condition and the slow-wave sleep, and increases during the active states of alert cats. In paradoxical sleep the signal transmission is at the same level as such at resting wakeful condition. A marked transmission fluctuation is seen during the dreaming state and in the course of the first phase of sleep. The level of signal transmission is the most stable during the active states. The degree of the trance inhibitory process after the afferent signal transmission depends on the level of anesthesia, wakefulness and natural sleep. Processes following the afferent signal transmission in the posterior ventral nucleus of the thalamus show a radical difference in the barbituiate-anesthetized in comparison with nonanesthetized animals. The trace inhibition, so characteristic of anesthesia, was expressed in the dreaming state of the animal but insignificantly; in the wakeful condition it is not manifested at all.

Anesthesia, General↗
PubMed1976

[A neurophysiologic analysis of the effect of amidopyrine at the thalamo-cortical level of the somatosensory system].

Acute experiments were conducted on nonanesthetized cats; it was shown that amidopyrin (10, 20 mg/kg, intravenously) decreased the level of the background activity of the thalamic neurons, and, at the same time, increased the amplitude of the focal primary bioelectrical reactions. It is supposed that amidopyrin synchronized evoked reactions of the cells in the thalamus, as well as in the cortex. On the other hand, amidopyrin diminished the excitability of the cortical neurons participating in the interzonal connections.

Aminopyrine↗
PubMed1976

[The effect of hypertonic solutions on the electrical activity of isolated frog muscle spindles].

Electrical activity of an isolated frog muscle spindle was investigated in hypertonic solutions obtained by adding 400 mM of sucrose, glucose or glycerine to the Ringer solution. In sucrose and glucose hypermedia the frequency of background impulse activity first increased and then decreased up to zero; receptor potentials and evoked impulse activity simultaneously decreased and disappeared. In the glycerine hypermedia impulse activity after some increase returned to normal and then a second rise of frequency to a constant supernormal level was observed. After returning to the Ringer solution from sucrose or glucose the background and evoked impulse activity progressively returned to normal. But after glycerine hypermedia a significant growth in the background impulse activity and a small change in frequency of evoked impulse activity were observed. The observed changes of electrical activity of the muscle spindle in hypermedia are discussed in terms of deformation of sensory endings and intrafusal muscles fibres leading to depolarization of the receptor membrane.

Animals↗
PubMed1976

[Influence of adequate stimulation on the impulse electrical activity of isolated frog muscle spindles].

Impulse activity of an isolated frog muscle spindle was investigated using mechanical stimulation of various amplitude, rate and form. It is found out that firing frequency during linear-increasing stimulation is determined by the amplitude of the stimulus and alteration of firing frequency by the rate of the stimulation increase. At sinusoidal stimulation the impulsation "repeates" the form of the stimulus, i.e. the muscle spindle is influenced not only by its amplitude or rate, but also by its acceleration. The sensitivity to accelerations may depend on changes in discharge threshold during alteration of the tension rate change.

Action Potentials↗
PubMed1976

[Influence of the somatic region of the cortex on trace inhibitory processes in the posterior lateral nucleus of the thalamus].

Acute experiments were conducted on cats under nembutal anesthesia. A study was made of the dynamics of the changes occurring in the curve of restoration of the test response amplitude in the thalamo-cortical fibers to the pared stimulation of the medial lemniscus with various actions on the somatosensory ared. The curve under study served as an indicator of the corticofugal influences on the inhibitory after process in the transmission nucleus of the thalamus. The influences on one somatosensory area of the cortex blocked the transmission of the afferent signals in 70% of the neurons of the transmission nucleus of the thalamus. A correlation between the number of the neurons participating in the reaction and the character of the initial phase of the inhibitory afterprocess was noted.

Animals↗
PubMed1975

[Role of sensory signals in the development of cortical influences on hypothalamic structures].

Neuron discharges of the hypothalamic ventro-medial and posterior nuclei were registered in immobilized cats during electrical stimulation of the ipsi- and contralateral nerves of the brachial plexus, the 1st and the 2nd somatosensory regions (SI and SII) and the visual regions of the cortex and the reticular formation (RF) of the mesencephalon. A reversible cold block of the SI and SII failed to change the effect of the nerve stimulation. Stimulation of the postero-ventral thalamic nucleus did not change the initial activity of the hypothalamic neurons and gave rise to no neuron activity that appeared on stimulation of the SII. A conclusion was drawn that cortico-hypothalamic influences that appeared on stimulation of the nerves and the postero-ventral nucleus of the thalamus were pronounced weakly.

Animals↗
PubMed1975

[Projections of the somatosensory areas of the cerebral cortex into the thalamic nuclei].

Results of morphological studies of degenerated fibers indicated that the first somatosensory area of the cortex was connected by the descending cortico-thalamic fibers with the posterior ventral nucleus of the thalamus. The second somatosensory area was simultaneously connected with the caudal portion of the posterior ventral nucleus and with the nuclei of the posterior group of the thalamus. The mentioned cortico-thalamic connections were distributed by the somatotopic principle.

Afferent Pathways↗