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.
Hurwitz
I
I
Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York 10029, USA.
Perrins
R
R
Xin
Y
Y
Weiss
K R
KR
Kupfermann
I
I
D000818:Animals; D001048:Aplysia; D048429:Cell Size / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D017952:Ganglia, Invertebrate / Q000502:physiology; D066298:In Vitro Techniques; D007395:Interneurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism*; D018408:Patch-Clamp Techniques
D009479:Neuropeptides; C053302:myomodulin