Microinjections of subpicomolar amounts of NPY(13-36) into the nucleus tractus solitarius of the rat counteract the vasodepressor responses of NPY(1-36) and of a NPY Y1 receptor agonist.
Microinjections of neuropeptide Y (NPY) (1-36) and of the NPY Y1 agonist [Leu31,Pro34]NPY into the caudal dorsomedial part of the nucleus tractus solitarius (Sol) in the anaesthetized rat led to the development of dose-related vasodepressor and bradycardic responses. The threshold dose of the NPY Y2 agonist NPY(13-36) (50 fmol) significantly counteracted the vasodepressor actions of a close to ED50 dose of NPY(1-36) (2.5 pmol) and of the NPY Y1 agonist (5 pmol). These results indicate that NPY Y1 receptor activation in the Sol leads to the development of a vasodepressor response, which can be counteracted by NPY Y2 receptor activation in the Sol. The results support the existence of a Y2/Y1 receptor-receptor interaction in the Sol, via which NPY Y2 receptors may reduce transduction over NPY Y1 receptors.
Yang
S N
SN
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
Narváez
J A
JA
Bjelke
B
B
Agnati
L F
LF
Fuxe
K
K
D000818:Animals; D004305:Dose-Response Relationship, Drug; D008297:Male; D008845:Microinjections; D009478:Neuropeptide Y / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors*; D010446:Peptide Fragments / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011964:Receptors, Gastrointestinal Hormone / Q000187:drug effects*; D017552:Solitary Nucleus / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*
D009478:Neuropeptide Y; D010446:Peptide Fragments; D011964:Receptors, Gastrointestinal Hormone; D014662:Vasoconstrictor Agents; C062924:neuropeptide Y (13-36); C082172:peptide YY receptor; C062259:neuropeptide Y, Leu(31)-Pro(34)-