Activity-dependent peptidergic modulation of the plateau-generating neuron B64 in the feeding network of Aplysia.
Many behaviors display various forms of activity-dependent plasticity. An example of such plasticity is the progressive shortening of the duration of protraction phase of feeding responses of Aplysia that occurs when feeding responses are repeatedly elicited. A similar protraction-duration shortening is observed in isolated ganglia of Aplysia when feeding-like motor programs are elicited through a prolonged stimulation of the command-like neuron CBI-2. Here, we investigate a cellular mechanism that may underlie this activity-dependent shortening of protraction duration of feeding motor programs. CBI-2 contains two neuropeptides, CP2 and FCAP. Previous work showed that CP2 shortens protraction duration of CBI-2 elicited programs. We show here that the same is true for FCAP. We also show that both CP2 and FCAP modulated the biophysical properties of a plateau-generating neuron, B64, that plays an important role in terminating the protraction phase of feeding motor programs. We find that prestimulation of CBI-2, as well as superfusion of CP2 and FCAP, lowered the threshold for activation of the plateau potential in B64. The threshold-lowering actions of CBI-2 prestimulation were occluded by superfusion of FCAP and CP2. Furthermore, at elevated temperature, conditions under which peptide release is prevented in Aplysia, prestimulation of CBI-2 does not lower the plateau-potential threshold, whereas superfusion of CP2 and FCAP does. Our findings are consistent with the hypothesis that peptides released from CBI-2 lower the threshold for activation of plateau potential in B64, thereby contributing to the shortening of protraction duration when CBI-2 is repeatedly activated.
Koh
Hae-Young
HY
Department of Neuroscience, Mount Sinai School of Medicine, 1 Gustave Levy Place, New York, NY 10029, USA.
Weiss
Klaudiusz R
KR
D000818:Animals; D001048:Aplysia / Q000502:physiology*; D001369:Axons / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D017952:Ganglia, Invertebrate / Q000502:physiology; D006358:Hot Temperature; D008564:Membrane Potentials / Q000187:drug effects; D009415:Nerve Net / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology*; D013268:Stimulation, Chemical
D009479:Neuropeptides