Dopaminergic contributions to modulatory functions of a dual-transmitter interneuron in Aplysia.
The feeding central pattern generator of Aplysia produces motor programs that can differ in the degree to which they are ingestive or egestive. A number of pattern-generating interneurons that play an important role in shaping motor programs have been identified. One of these interneurons, B65, is unusual in that it contains two classical neurotransmitters, dopamine and gamma-aminobutyric acid. Here, we study the role of one of these transmitters, dopamine, using a combination of pharmacological and electrophysiological means. We show that B65 uses dopamine to elicit fast synaptic potentials in several follower neurons. Furthermore, we demonstrate that the dopamine antagonist sulpiride mimics the effect of bilateral B65 hyperpolarization on egestive motor programs. Thus our data suggest that dopaminergic transmission serves to increase the degree of egestiveness of motor programs, and decrease the duration of the protraction phase.
Due
Michael R
MR
Department of Physiology and Biophysics, Mount Sinai School of Medicine, Box 1218, New York, NY 10029, USA.
Jing
Jian
J
Weiss
Klaudiusz R
KR
D000818:Animals; D001048:Aplysia / Q000187:drug effects* / Q000502:physiology; D004298:Dopamine / Q000494:pharmacology* / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D007395:Interneurons / Q000187:drug effects* / Q000502:physiology; D009061:Mouth Mucosa / Q000187:drug effects / Q000502:physiology; D013469:Sulpiride / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology
D005680:gamma-Aminobutyric Acid; D013469:Sulpiride; D004298:Dopamine