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Biomedical subjects

K Walton

Publications and source records attributed to K Walton.

5 recordsLinked to original sources

Presynaptic calcium currents and their relation to synaptic transmission: voltage clamp study in squid giant synapse and theoretical model for the calcium gate.

A voltage clamp study of the presynaptic terminal in squid stellate ganglion has given quantitative results relating inward Ca2+ current to presynaptic membrane potential and postsynaptic response to inward Ca2+ current. The results indicate an S-shaped curve for the relationship between presynaptic potential and Ca2+ current and a linear relationship between Ca2+ current and postsynaptic potential. A similar S-shaped curve was found for the time-dependent properties of the Ca2+ conductance. Based on these results a mathematical model was developed which accounts for the experimental results in this and previously published papers by other authors. The model suggests that five subunits are involved in the Ca2+ gate and that the subunits change noncooperatively from an inactive to an active form upon membrane depolarization.

Animals

Inferior olive: its role in motor learing.

Specific chemical lesion of the rat inferior olive by intraperitoneal administration of 3-acetylpyridine prevents recuperation from motor abnormalities generated by unilateral labyrinthine lesion. Moreover, in animals that have recuperated from the balyrinthine lesion, 3-acetylpyridine produces a reversal of the symptoms within 2 hours of administration. These results indicate that the integrity of the olivo-cerebellar system is necessary for the acquisition and retention of this form of motor learning, but that the cerebellum itself is not the seat of such learning.

Animals