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Ontogenetic study of evoked potentials from cerebral cortex and cerebellum in cats
636
JOURNAL OF EVOLUTIONARY BIOCHEMISTRY AND PHYSIOLOGY
resistance and specific capacitance of the cell membrane unless its submicroscopic structure has been duly considered. It has been shown that in Planorbis corneus functional connexions between individual neurons are realized at the level of axon-axonal synapses. Three types of synaptic vesicles have been revealed; their submicroscopic organization suggests that in addition to a cholinergic mechanism of synaptic transmission, a non-cholinergic type of transmission may exist in the nervous system of Mollusca.
Electrical activity o f giant neurons o f the nudibranchiate mollusc Tritonia diomedia: By V. D . GERASIMOV a n d I. S. MAGURA: I n s t i t u t e of P h y s i o l o g y o f t h e A c a d e m y o f S c i e n c e s of t h e U k r . S S R , K i e v , p p . 360-363. NERVE cells of nudibranchiate molluscs Tritonia diomedia represent a convenient object for electrophysiological investigation due to their large size (according to the authors' observations, their diameter attains 800/~). T h e average resting potential of these cells is 45-50 mV, amplitude of the action potential being about 80-100 mV. On direct stimulation of the cell body with impulses of a depolarizing current it often generates action potentials, showing a hump on the descending limb, or a double (split) peak. Hyperpolarization current applied to the cell usually eliminates both peak splitting and the hump of the descending part of the action potential. T h e descending part of the action potential has been found to merge into trace hyperpolarization. Its amplitude amounts to 10-20 mV, and duration to about 100 msec. Input capacity has been shown to vary considerably--between 4"0 x 10 -2 and 40 x 10 -2 /zF as well as the input resistance--between 2"5 x 105 k~ and 18 x 105 D, depending on the size of the cell.
Ontogenetlc study o f evoked potentials f r o m cerebral cortex and cerebellum in cats: B y L. S. MUROVA: I n s t i t u t e o f E v o l u t i o n a r y P h y s i o l o g y a n d B i o c h e m i s t r y o f t h e A c a d e m y o f S c i e n c e s o f t h e U S S R , L e n i n g r a d , p p . 364-373. EVOLUTION of evoked potentials (EP) from sensory-motor cortex and cerebellum in response to stimulation of the central end of the sciatic nerve has been studied in kittens aged from 1 day to 3 months. As early as on the first postnatal day, EP was recorded from the cerebral cortex as a monophase negative wave with long latency (120-90 msec). F r o m the fifth to seventh days of life it came to be preceded by initial positivity. T h e first cerebgllar responses of positive sign and long latency were recorded on the fifth to seventh postnatal day. Augmentation of amplitude, reduction of latency, with decreasing response thresholds, progressed with particular rapidity within the first 3-4 weeks of life. At an early posnatal period (within 2 weeks) aptitude to reproduce the rhythm of stimulation was more apparent in the cerebral cortex, this capacity being displayed better by cerebellar activity after 4-5 weeks age. T h e effect of 7-aminobutyric acid on cortical responses could be revealed from the first postnatal days, while cerebellar responses were only influenced after the third week of life.
Effect o f carnosine on contractile and enzymatic properties o f actomyosin: B y I. M . BOCHARNIKOVA a n d E. V. PETUSHKOVA: U n i v e r s i t y of M o s c o w , p p . 3 8 5 390. IN MODEL experiments on compressed monolayers of actomyosin (film threads) prepared according to T. Hayashi's technique, carnosine has been shown to prevent the plastifying effect of adenosinetriphosphate (ATP) on the threads. T h e effect of carnosine was not related to any change in ATPase activity of actomyosin. Demonstration of the "carnosine
JOURNAL OF EVOLUTIONARY BIOCHEMISTRY AND PHYSIOLOGY
resistance and specific capacitance of the cell membrane unless its submicroscopic structure has been duly considered. It has been shown that in Planorbis corneus functional connexions between individual neurons are realized at the level of axon-axonal synapses. Three types of synaptic vesicles have been revealed; their submicroscopic organization suggests that in addition to a cholinergic mechanism of synaptic transmission, a non-cholinergic type of transmission may exist in the nervous system of Mollusca.
Electrical activity o f giant neurons o f the nudibranchiate mollusc Tritonia diomedia: By V. D . GERASIMOV a n d I. S. MAGURA: I n s t i t u t e of P h y s i o l o g y o f t h e A c a d e m y o f S c i e n c e s of t h e U k r . S S R , K i e v , p p . 360-363. NERVE cells of nudibranchiate molluscs Tritonia diomedia represent a convenient object for electrophysiological investigation due to their large size (according to the authors' observations, their diameter attains 800/~). T h e average resting potential of these cells is 45-50 mV, amplitude of the action potential being about 80-100 mV. On direct stimulation of the cell body with impulses of a depolarizing current it often generates action potentials, showing a hump on the descending limb, or a double (split) peak. Hyperpolarization current applied to the cell usually eliminates both peak splitting and the hump of the descending part of the action potential. T h e descending part of the action potential has been found to merge into trace hyperpolarization. Its amplitude amounts to 10-20 mV, and duration to about 100 msec. Input capacity has been shown to vary considerably--between 4"0 x 10 -2 and 40 x 10 -2 /zF as well as the input resistance--between 2"5 x 105 k~ and 18 x 105 D, depending on the size of the cell.
Ontogenetlc study o f evoked potentials f r o m cerebral cortex and cerebellum in cats: B y L. S. MUROVA: I n s t i t u t e o f E v o l u t i o n a r y P h y s i o l o g y a n d B i o c h e m i s t r y o f t h e A c a d e m y o f S c i e n c e s o f t h e U S S R , L e n i n g r a d , p p . 364-373. EVOLUTION of evoked potentials (EP) from sensory-motor cortex and cerebellum in response to stimulation of the central end of the sciatic nerve has been studied in kittens aged from 1 day to 3 months. As early as on the first postnatal day, EP was recorded from the cerebral cortex as a monophase negative wave with long latency (120-90 msec). F r o m the fifth to seventh days of life it came to be preceded by initial positivity. T h e first cerebgllar responses of positive sign and long latency were recorded on the fifth to seventh postnatal day. Augmentation of amplitude, reduction of latency, with decreasing response thresholds, progressed with particular rapidity within the first 3-4 weeks of life. At an early posnatal period (within 2 weeks) aptitude to reproduce the rhythm of stimulation was more apparent in the cerebral cortex, this capacity being displayed better by cerebellar activity after 4-5 weeks age. T h e effect of 7-aminobutyric acid on cortical responses could be revealed from the first postnatal days, while cerebellar responses were only influenced after the third week of life.
Effect o f carnosine on contractile and enzymatic properties o f actomyosin: B y I. M . BOCHARNIKOVA a n d E. V. PETUSHKOVA: U n i v e r s i t y of M o s c o w , p p . 3 8 5 390. IN MODEL experiments on compressed monolayers of actomyosin (film threads) prepared according to T. Hayashi's technique, carnosine has been shown to prevent the plastifying effect of adenosinetriphosphate (ATP) on the threads. T h e effect of carnosine was not related to any change in ATPase activity of actomyosin. Demonstration of the "carnosine