Search PubMed⌕ Search

Biomedical subjects

Iu V Panchin

Publications and source records attributed to Iu V Panchin.

At least 19 recordsLinked to original sources
PubMed1991

[Electrophysiologic study of the serotoninergic neuron C1 in the pteropod mollusk Clione].

Functional characteristics of the cerebral serotoninergic neuron (C1) have been studied in the pteropod mollusc Clione limacina. The C1 neuron axon projected to the buccal ganglia and axon collaterals terminated in buccal nerves. Stimulation of the C1 neuron activated the feeding rhythm generator in the buccal ganglia. Effects developed relatively slowly and far outlasted the period of C1 neuron stimulation. The C1 neuron received synaptic feedback from buccal neurons. As a result, the C1 neuron activity was cyclically modulated with respect to feeding rhythm generation. There was a correlation between the activity of the C1 neurons and that of the locomotor generator located in the pedal ganglia. Activation of the locomotor generator, both spontaneous and evoked by stimulation of some command neurons, was accompanied by excitation of the C1 neurons. The correlation between the activities of the locomotor generator and of the C1 neurons is suggested to be one of manifestations of the feeding synergy including simultaneous activation of the locomotor and buccal systems.

Animals↗
PubMed1990

[The neuronal mechanisms of the defensive reaction to stimulation of the cutaneous nerve in the freshwater snail].

The whole body withdrawal reaction of freshwater snail Planorbarius corneus consists of two phases. In the first phase the shell is rapidly moved down to cover the head, in the second one the body is slowly retracted into the shell. The columellar muscle is involved in this behaviour. Motoneurons of the columellar muscle are identified in the cerebral, parietal and pedal ganglia. In the preparation of the central nervous system connected with the columellar muscle it is demonstrated that stimulation of the lip nerve evoked a biphasic motoneuron excitation responsible for two phases of the muscle contraction. A similar biphasic excitation of the motoneurons could arise spontaneously. This implies that the whole body withdrawal reaction is, at least partly, a fixed act generated by a central mechanism (a central program) which is triggered by a sensory stimulus. The central mechanism of the withdrawal reaction could be also activated by a depolarization of some columellar motoneurons. This suggests that the central mechanism received a feedback from the motoneurons.

Animals↗
PubMed1990

[The neuronal mechanisms of the escape reaction to stimulation of the statocyst receptors in the freshwater snail].

Tilts of the freshwater snail Planorbarius corneus, resulting in statocyst receptor stimulation, induced the defensive reaction including pulling down of the shell, shortening of the foot, inhibition of locomotion and feeding. The preparation of the central nervous system has demonstrated that many inter- and motoneurons from different ganglia were involved in this reaction. Usually the reaction was of "all or none" manner. The repeated reaction of the second tilt could be evoked not earlier than 10-20 s after the previous one. It is concluded that the defensive reaction to statocyst receptor stimulation is a "fixed act" determined by a special central mechanism (a central program). The reactions to stimulation of statocyst receptors and skin nerve are proved to be generated by the same mechanism.

Animals↗
PubMed1990

[The generation of locomotor rhythmicity in the nervous system of large and small individuals of the pteropod mollusk Clione limacina].

The marine pteropod mollusc Clone limacina swims due to rhythmic movements of its wings. The frequency of wing oscillations in young molluscs (2-6 mm long) is 5-6 Hz, while in adult molluscs (40-60 mm long) it is 1-2 Hz. The locomotor rhythm is generated by two groups of pedal interneurons (groups 7 and 8) capable of endogenous rhythmic activity. The interneurons generate prolonged action potentials, one potential per a locomotor cycle. Action potentials generated by interneurons in young molluscs are found to be shorter (30-40 ms) than in adult ones (100-150 ms). This difference in duration of the action potentials is a result of the higher frequency of the locomotor rhythm in young molluscs as compared with adult ones.

Action Potentials↗
PubMed1988

[Neuronal mechanisms of the generation of the feeding rhythm in the buccal ganglia of the pteropod mollusk].

Two antagonistic groups of neurons, active in protractor and retractor phases of the feeding cycle, were found in the buccal ganglia of the pteropod mollusc Clione limacina. Neurons within each group are electrically coupled, while the groups inhibit one another. Each group is able to perform independent rhythmic activity. When the activity of one of the groups terminates (due to inner reasons), the other group becomes active (due to both the inner tendency of generating periodic bursts and the postinhibitory rebound).

Animals↗
PubMed1985

[Generation of locomotor rhythms in Limacina helicina].

Two groups of neurons (motoneurons and putative interneurons), exhibiting periodic activity with the locomotory rhythm, were recorded in the pedal ganglia of the isolated nervous system of the mollusc Limacina helicina. Motoneurons periodically generated spike bursts, while interneurons generated only one prolonged (100-400 ms) action potential per cycle. Rhythmic generation persisted after blocking the spike discharges of motoneurons by means of tetrodotoxin. Rhythmic generation could be facilitated by application of serotonin.

Action Potentials↗
PubMed1985

[Regeneration of neurons of the pedal ganglion of the pteropodal mollusk Clione limacina].

In pedal ganglia of mollusc Clione limacina the growth of axons was studied in motoneurons and interneurons after transections of the wing nerve or of the pedal comissure. Neurons were stained by Lucifer Yellow. In motoneurons, neurites grown both from the transected end of the axon and from the neuron soma spread to all nerve trunks of ipsi- and contralateral ganglia. After nerve transection in the whole mollusc, wing movements restored 10 days later. In interneurons, neurites branched within the pedal ganglion or spread into cerebral ganglia but they did not extend out peripheral nerve trunks. Thus, the patterns of neurite sprouting in moto- and interneurons are different.

Animals↗
PubMed1984

[Interneuron activity of the pedal ganglia of pteropod mollusks during generation of locomotor rhythms].

Activity of interneurons from isolated pedal ganglia of marine mollusc Clione limacina was recorded during generation of the locomotor rhythm. Two groups of reciprocally active interneurons were found. These neurons generate one prolonged action potential per locomotory cycle. Inhibitory interaction between the two groups was observed. The interneurons were supposed to generate the locomotor rhythm.

Animals↗
PubMed1984

[Synchronization of the work of pedal ganglia of pteropod mollusks during locomotion].

Two wings of the marine mollusc Clione limacina oscillate synchronously during swimming. These movements are controlled by pedal ganglia. Synchronization of rhythmic activities in the ganglia is produced by interneurons of groups 7 and 8 whose axons pass to the contralateral ganglion through the pedal commissure. After destruction of commissural pathways, rhythmic activities in the two ganglia become independent. The synchronization restores with the regeneration of axons of interneurons from groups 7 and 8.

Animals↗
PubMed1984

[Neurons of the pedal ganglia of a pteropod mollusk regulating locomotor generator function].

Neurons whose excitation affected the locomotory rhythm were recorded in the isolated pedal ganglia of the marine mollusc Clione limacina. Some of these neurons generated "plateau" potentials, i.e. they remained depolarized for a long period after termination of the initial depolarizing current. A role of the command neurons in the motor behaviour of Clione is discussed.

Animals↗
PubMed1978

[Depolarization of primary afferents during fictitious scratching of thalamic cats].

The cord dorsum and dorsal root potentials were recorded during fictious scratching in L6 segment of the thalamic cats. It is shown that primary afferent depolrization (PAD) can be modulated by the central generator of scratching. In some afferent fibres antidromic spikes appear on the top of PAD-waves. Antidromic spikes can be also evoked in the period of "rest" by mechanical stimulation of hindlimb receptors. It is supposed that PAD and resulting antidromic spikes which appear during real scratching may effectively control the level of afferent inflow to the spinal neurons.

Animals↗
PubMed1978

[Vestibular responses of "fast" and "slow" Deiter's nucleus neurons].

The response of vestibulospinal neurons to the tilt in the frontal plane was studied in decerebrate cats. The neurons were identified antidromically by L1 stimulation. The response to the tilt was found to be correlated with the speed of axonal conductance: the neurons responding to the ipsilateral tilt had the latency of the antidromic response 2.8 +/- 0.7 ms, while those responding to the contralateral tilt--4.6 +/- 2.0 ms.

Animals↗