Sequential modification of membrane currents with classical conditioning.
Pavlovian conditioning of the nudibranch mollusc Hermissenda crassicornis was previously shown to produce long-lasting reduction of two K+ currents measured across the Type B photoreceptor soma membrane (Alkon et al., 1982a; Alkon et al., 1985). Pavlovian conditioning of the rabbit was also shown to be followed by persistent K+ current reduction (Disterhoft et al., 1986). Here we report the first evidence that Ca2+ currents can also be modified by conditioning. The amplitude of the currents rather than their voltage-dependence remains reduced at least 1-2 d after conditioning (but not control procedures). Conditioning-induced changes of both K+ and Ca2+ currents increased as a function of training, the Ca2+ currents only changing substantially with greater than or equal to 250 trials. The later changes of the Ca2+ current may function to limit the magnitude of excitability increases due to associative learning.
Collin
C
C
Section on Neural Systems, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, Maryland 20892.
Ikeno
H
H
Harrigan
J F
JF
Lederhendler
I
I
Alkon
D L
DL
D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D003214:Conditioning, Classical; D004553:Electric Conductivity; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008974:Mollusca / Q000502:physiology*; D010786:Photoreceptor Cells / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*
D015220:Calcium Channels; D015221:Potassium Channels