Subpicomolar amounts of NPY(13-36) injected into the nucleus tractus solitarius of the rat counteract the cardiovascular responses to L-glutamate.
The effects of NPY(13-36) on cardiorespiratory responses elicited by microinjections of L-glutamate into the nucleus tractus solitarius (NTS) have been studied in anaesthetized (alpha-chloralose + urethane) Sprague-Dawley rats. NPY(13-36) in doses ranging from 50 to 500 fmol produces a significant increase in mean arterial pressure (MAP) without significant effects on heart rate (HR) and respiratory rate (RR). The ED50 dose (100 fmol) of NPY(13-36) counteracts significantly the decrease in MAP and HR elicited by L-glutamate (1500 pmol) microinjected into NTS. Similar results are obtained using a threshold dose of the peptide (50 fmol) and an ED50 dose of L-glutamate (300 pmol). These results indicate that the Y2 receptors in NTS can mediate vasopressor responses to femtomolar amounts of NPY(13-36) and counteract cardiovascular responses to L-glutamate.
Narváez
J A
JA
Department of Physiology, University of Malaga, Spain.
Aguirre
J A
JA
Fuxe
K
K
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005070:Evans Blue; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007267:Injections; D008297:Male; D008526:Medulla Oblongata; D008845:Microinjections; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000494:pharmacology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects; D013239:Stereotyped Behavior / Q000187:drug effects
D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates; D009478:Neuropeptide Y; D010446:Peptide Fragments; C062924:neuropeptide Y (13-36); D018698:Glutamic Acid; D005070:Evans Blue