[Change in the background afferent influx to the spinal cord after transsecting the sciatic nerve and early enhancement of monosynaptic reflexes]. / Izmenenie fonovogo afferentnogo pritoka k spinnomu mozgu posle pererezki sedalishchnogo nerva i rannee usilenie monosinapticheskikh refleksov.

Background impulse activity (BIA) of separate fibres of dorsal roots of 5 lumbar segment of rats after one-sided cutting of the sciatic nerve which caused early enhancement of monosynaptic segmental reflexes (5 days after operation) has been recorded. It is revealed that afferent fibres with BIA are found more rarely on side of cutting than on the opposite side and frequency of background activity is lower than in the opposite root. It is concluded that development of spontaneous activity of the spinal ganglion neurons after cutting nerves does not ensure a higher BIA level in afferent fibres. The given phenomenon cannot be a reason of early enhancement of monosynaptic reflexes after the nerve cutting.

[Evoked activity of spinal cord neurons in the early period after cutting the sciatic nerve]. / Vyzvannaia aktivnost' neironov spinnogo mozga v rannie sroki posle pererezki sedalishchnogo nerva.

The character of evoked activity of motoneurons, interneurons and Renshaw cells of white rats in low lumbar segments of the spinal cord was studied 5 days after cutting of sciatic nerves. A trustworthy rise of the amplitude of the excited postsynaptic potential (EPSP) of motoneurons on the side of nerve cutting was found. No reliable change of the membrane potential and threshold of the action potential emergence in these motoneurones was observed. Character of evoked activity of the Renshaw cells and interneurons did not differ essentially from the same of animals with the intact nerve. Possible mechanisms taking part in rising of the EPSP amplitude after cutting of the nerve are discussed.

[Segmental reflexes after sciatic nerve damage in rats given thyroxine]. / Osobennosti segmentarnykh refleksov posle povrezhdeniia sedalishchnogo nerva u tiroksinizirovannykh krys.

Amplitude of the L5 segmental reflex responses 20 min. before and after intraperitoneal introduction of obsidan, clopheline and finoptine was recorded in experiments on spinalized and thyroxinized rats which 3 weeks before have endured transection of the sciatic nerve. It is demonstrated that obsidan does not change the amplitude of the monosynaptic reflex responses of the ventral root restored under the effect of thyroxine at the operated side, while clopheline and finoptine mainly reduce it.

[The possible role of changes in calcium conduction in the early enhancement of spinal reflex responses after dissection of the sciatic nerve]. / Vozmozhnaia rol' izmenenii kal'tsievoi provodimosti v rannem usilenii spinal'nykh reflektornykh otvetov posle pererezki sedalishchnogo nerva.

Effects of imidazol, 4-aminopyridin and verapamil on evoked monosynaptic responses 5-7 days after cutting of the sciatic nerve have been studied in white rats. Imidazol induced no changes for certain 4-aminopyridin increased and verapamil decreased amplitude of responses on the side of cutting nerve.

[Effect of tractotomy on the reflex activity of the lumbar segment of the spinal cord severed after sectioning of the sciatic nerve in the rat]. / Vliianie khordotomii na reflektornuiu aktivnost' poiasnichnogo otdela spinnogo mozga krys, narushennuiu posle pererezki sedalishchnogo nerva.

Electrical responses of the spinal cord roots of rats evoked by the preliminary cutting of nerve were investigated in 1, 3, 7 and 14 days after tractotomy. Mean amplitude of the monosynaptic reflex discharges in ventral roots on the side of nerve section is substantially higher 7 and 14 days after the tractotomy, than that of these responses 1 and 3 days after it.

[Effect 4-aminopyridine on the recovery of segmental reflexes after sectioning of the sciatic nerve in the rat]. / Vliianie 4-aminopiridina na vosstanovlenie segmentarnykh refleksov posle pererezki sedalishchnogo nerva u krys.

L5 ventral root reflex discharges evoked by dorsal root stimulation were studied 3-4 weeks after transection of sciatic nerve in rats; only polysynaptic transmission was found on the side of operation. Injection of 4-aminopyridine (500-600 mg/kg, intraperitoneally) resulted in facilitation of reflex discharges on the intact side and in reappearance of intensive monosynaptic component in such discharges on the affected side. It is concluded that 4-aminopyridine recovers monosynaptic transmission between primary afferents and chromatolysed motoneurons because of increased transmitter liberation.

[Antidromic electrical activity of the motor endings of the neuromuscular synapses in rats during acetylcholinesterase inhibition]. / Antidromnaia élektricheskaia aktivnost' morornykh okonchanii nervno-myshechnykh sinapsov krys pri ingibirovanii atsetilkholinésterazy.

In acute experiments on spinal rats antidromic potential amplitude was studied in the peripheral processes of the anterior roots of the lumber segments elicited by a solitary and rhythmical stimulation of the tibial nerve before and after i. p. injection of proserine (0.3-0.5 mg/kg). After the injection solitary stimulation of the nerve evoked an antidromic electrical activity in the peripheral processes of the anterior root whereas rhythmical stimulation resulted in depression of the antidromic potentials. The antidromic potential depression seems to indicate an initial transmitter discharge into neuromuscular synapses.

[Reflex responses during the early period of recovery of motor function in a transplanted limb]. / Reflektornye reaktsii v rannii period vosstanovleniia dvigatel'noi funktsii peresazhennoi konechnosti

In immobilized anesthetized rats, monosynaptic reflex responses before and after (3 months) the autoreplantation of the left hind limb were studied. The early period after replantation was characterized by the lowering of excitability, the increase of latency, the decrease of differences between reflex responses to nerves stimulation. Differences existed between responses to stimulation of flexors and extensors but only with a major time summation which suggested that they were due to dendrite processes in chromatotized motoneurons.