Search PubMedSearch

PubMed · 1080808

[On decrease in spike height of nerve action potential. A comparison between sciatic nerve and ENM (author's transl)].

Abstract

Employing ENM and a sciatic nerve removed from bullfrog, configuration of decrease of spike under various experimental conditions was studied. The amplitude of the membrane potential change in excitation was also recorded simultaneously with the decrease of spike in ENM (electric nerve model). Both on the nerve and ENM, with decrease of the resting potential, the amplitude of the spike and the amplitude of the change of the membrane potential were decreased. On the nerve and ENM, the decrease in spike amplitudes was induced by an elevation of the niveau and by a lowering of the top. However, the amplitude of the change of membrane potential of ENM was reduced only from the base of the spike due to an elevation of the niveau, with the top remained at a constant level. These decreases of the spike amplitude and the change of the membrane potential in nerve were consistent with that the electric constitution was the same for nerve and ENM, which is the experimental equivalent circut of the nerve fiber devised by the authors.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M Matumoto, T Kitamura, M Hanba. 1975. [On decrease in spike height of nerve action potential. A comparison between sciatic nerve and ENM (author's transl)].. https://pubmed.ncbi.nlm.nih.gov/1080808/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The function relating the subjective magnitude of brain stimulation reward to stimulation strength varies with site of stimulation.

A two-lever choice paradigm with concurrent variable interval schedules of reward was used to measure the growth in the subjective magnitude of reward as a function of current, by finding the adjustment in the stimulating current required to offset a given difference in the rates at which two rewards were received. Increasing current by a factor of 2 increased subjective reward magnitude by a factor ranging from as little as 3 to as much as 4,000. This range was about as great between electrodes within one rat as between electrodes and rats. In the light of earlier findings regarding the equivalent effects of increments is current and pulse frequency, these large differences cannot readily be explained by differing fiber densities at the site of stimulation. It is suggested that the medial forebrain bundle terminates in more than one spatio-temporal integration mechanism. The magnitude of the spatio-temporally integrated effect of a barrage of action potentials in the reward-relevant axons depends on which subset of reward-relevant axons is excited by the stimulation.

Action Potentials

Effect of substance P on circadian rhythms of firing activity and the 2-deoxyglucose uptake in the rat suprachiasmatic nucleus in vitro.

The suprachiasmatic nuclei (SCN) have been identified as a pacemaker for many circadian rhythms in mammals. Although substance P (SP) fibers from retina are found to terminate the SCN, the physiological role of this peptide is uncertain. The 2-deoxyglucose (2-DG) uptake and firing activity in the SCN show a robust circadian change. SP causes an increase in 2-DG uptake by SCN during the subjective night but not during subjective day. SP-induced increase in 2-DG uptake is blocked by co-treatment with the SP receptor antagonist, spantide. Treatment with SP produces phase shifts of circadian rhythm in spontaneous neural activity in SCN neurons with a phase-response curve that is similar to the effect of light pulses to animals under constant darkness. SP-induced phase change is also blocked by pretreatment with spantide. SP-induced increase in 2-DG uptake and phase changes in firing activity occur only during subjective night, at circadian times when photic phase shifting of activity occurs. The present results suggest that SP may be an important transmitter for conveying environmental light-dark information from retina to the SCN.

Action Potentials

Activity-dependent decrease in NMDA receptor responses during development of the visual cortex.

Plasticity of the developing visual system has been regarded as the best model for changes of neuronal connections under the influence of the environment. N-methyl-D-aspartate (NMDA) receptors are crucial for experience-dependent synaptic modifications that occur in the developing visual cortex. NMDA-mediated excitatory postsynaptic currents (EPSCs) in layer IV neurons of the visual cortex lasted longer in young rats than in adult rats, and the duration of the EPSCs became progressively shorter, in parallel with the developmental reduction in synaptic plasticity. This decrease in NMDA receptor-mediated EPSC duration is delayed when the animals are reared in the dark, a condition that prolongs developmental plasticity, and is prevented by treatment with tetrodotoxin, a procedure that inhibits neural activity. Application of L-glutamate to outside-out patches excised from layer IV neurons of young, but not of adult, rats activated prolonged bursts of NMDA channel openings. A modification of the NMDA receptor gating properties may therefore account for the age-dependent decline of visual cortical plasticity.

Action Potentials