Responses of Neurons of the Canine Area Postrema to Neurotransmitters and Peptides
Final rept. Oct 1981-Sep 1982
SOUTHEASTERN CENTER FOR ELECTRICAL ENGINEERING EDUCATION INC ST CLOUD FL
Pagination or Media Count:
The responses of 122 neurons in the area postrema of anesthetized dogs to 17 common transmitters and peptides were determined. Recordings were made from one barrel of a 7-barrel ionophoretic electrode. All neurons were silent at rest, but most could be detected and excited by application of glutamate. The glutamate response was a brief, high-frequency response of less than 1-sec duration. Excitatory responses were also found to histamine, norepinephrine, serotonin, dopamine, apomorphine, angiotensin II, neurotensin, leucine-enkephalin, vasoactive intestinal polypeptide VIP, thyrotropin-releasing hormone TRH, gastrin, vasopressin, and substance P. While most neurons were excited by dopamine and apomorphine, approximately half of those studied were excited by the other substances. Inhibitory responses were found to norepinephrine 6 of 15 cells and histamine 3 of 45 cells. No responses were found to acetylcholine, somatostatin, or cholecystokinin CCK. The responses to all 13 excitatory substances other than glutamate were similar. Typically these responses had a latency of 2-20 sec and lasted for 30 sec to 5 min on their first application. The frequency of discharge was usually low approx. 0.5 Hz.
- Anatomy and Physiology