fmrfamide and 1-4-dihydropyridine

In Aplysia sensory and motor neurons in culture, the contributions of the major classes of calcium current can be selectively examined while transmitter release and its modulation are examined. A slowly inactivating, dihydropyridine-sensitive calcium current does not contribute either to normal synaptic transmission or to any of three different forms of plasticity: presynaptic inhibition, homosynaptic depression, and presynaptic facilitation. This current does contribute, however, to a fourth form of plasticity--modulation of transmitter release by tonic depolarization of the sensory neuron. By contrast, a second calcium current, which is rapidly inactivating and dihydropyridine-insensitive, contributes to release elicited by the transient depolarization of an action potential and to the other three forms of plasticity.

Topics: Action Potentials; Animals; Aplysia; Cadmium; Calcium Channels; Cells, Cultured; Dihydropyridines; Electric Conductivity; FMRFamide; Motor Neurons; Neuronal Plasticity; Neurons, Afferent; Neuropeptides; Nifedipine; Serotonin; Synapses; Synaptic Transmission