C-PR Neuron of Aplysia Has Differential Effects on "Feeding" Cerebral Interneurons, Including Myomodulin-Positive CBI-12

• Published in: Journal of neurophysiology Vol. 81; no. 2; pp. 521 - 534
• Main Authors: Hurwitz, Itay, Perrins, Ray, Xin, Yuanpei, Weiss, Klaudiusz R, Kupfermann, Irving
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-02-1999
• Subjects: Animals; Aplysia; Cell Size - physiology; Central Nervous System - physiology; Evoked Potentials - physiology; Feeding Behavior - physiology; Ganglia, Invertebrate - physiology; In Vitro Techniques; Interneurons - cytology; Interneurons - metabolism; Interneurons - physiology; Marine; Neural Inhibition - physiology; Neural Pathways - physiology; Neurons - cytology; Neurons - physiology; Neuropeptides - metabolism; Patch-Clamp Techniques
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1999.81.2.521

  1 Department of Physiology and
Biophysics, Mount Sinai School of Medicine, New York 10029;
  2 Center for Neurobiology and Behavior,
College of Physicians and Surgeons, Columbia University, New York City,
New York 10032
C-PR neuron of Aplysia has differential effects on
"feeding" cerebral interneurons, including myomodulin-positive
CBI-12. Head lifting and other aspects of the appetitive
central motive state that precedes consummatory feeding movements in
Aplysia is promoted by excitation of the C-PR neuron. Food
stimuli activate C-PR as well as a small population of cerebral-buccal
interneurons (CBIs). We wished to determine if firing of C-PR produced
differential effects on the various CBIs or perhaps affected all the
CBIs uniformly as might be expected for a neuron involved in producing
a broad undifferentiated arousal state. We found that when C-PR was
fired, it produced a wide variety of effects on various CBIs. Firing of
C-PR evoked excitatory input to a newly identified CBI (CBI-12) the
soma of which is located in the M cluster near the previously identified CBI-2. CBI-12 shares certain properties with CBI-2, including a similar morphology and a capacity to drive rhythmic activity of the buccal-ganglion. Unlike CBI-2, CBI-12 exhibits myomodulin immunoreactivity. Furthermore when C-PR is fired, CBI-12 receives a polysynaptic voltage-dependent slow excitation, whereas, CBI-2 receives relatively little input. C-PR also polysynaptically excites other CBIs including CBI-1 and CBI-8/9 but produces inhibition in CBI-3. In addition, firing of C-PR inhibits plateau potentials in
CBI-5/6. The data suggest that activity of C-PR may promote the
activity of one subset of cerebral-buccal interneurons, perhaps those
involved in ingestive behaviors that occur during the head-up posture.
C-PR also inhibits some cerebral-buccal interneurons that may be
involved in behaviors in which C-PR activity is not required or may
even interfere with other feeding behaviors such as rejection or
grazing, that occur with the head down.
0022-3077/99
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Copyright © 1999 The American Physiological Society