Galanin-neuropeptide Y (NPY) interactions in central cardiovascular control: involvement of the NPY Y receptor subtype.
The interactions between neuropeptide Y (NPY), specifically through NPY Y(1) and Y(2) receptor subtypes, and galanin [GAL(1-29)] have been analysed at the cardiovascular level. The cardiovascular effects of intracisternal coinjections of GAL(1-29) with NPY or NPY Y(1) or Y(2) agonists, as well as quantitative receptor autoradiography of the binding characteristics of NPY Y(1) and Y(2) receptor subtypes in the nucleus of the solitary tract (NTS), in the presence or absence of GAL(1-29), have been investigated. The effects of coinjections of GAL(1-29) and the NPY Y(1) agonist on the expression of c-FOS immunoreactivity in the NTS were also studied. The coinjection of NPY with GAL(1-29) induced a significant vasopressor and tachycardic action with a maximum 40% increase (P < 0.001). The coinjection of the NPY Y(1) agonist and GAL(1-29) induced a similar increase in mean arterial pressure and heart rate as did NPY plus GAL(1-29), actions that were not observed with the NPY Y(2) agonist plus GAL(1-29). GAL(1-29), 3 nm, significantly and substantially (by approximately 40%) decreased NPY Y(1) agonist binding in the NTS. This effect was significantly blocked (P < 0.01) in the presence of the specific galanin antagonist M35. The NPY Y(2) agonist binding was not modified in the presence of GAL(1-29). At the c-FOS level, the coinjection of NPY Y(1) and GAL(1-29) significantly reduced the c-FOS-immunoreactive response induced by either of the two peptides. The present findings suggest the existence of a modulatory antagonistic effect of GAL(1-29) mediated via galanin receptors on the NPY Y(1) receptor subtype and its signalling within the NTS.
Díaz-Cabiale
Zaida
Z
Departamento de Fisiología, Facultad de Medicina, Campus de Teatinos s/n. 29080 Málaga, Spain.
Parrado
Concepción
C
Rivera
Alicia
A
de la Calle
Adelaida
A
Agnati
Luigi
L
Fuxe
Kjell
K
Narváez
José A
JA
D000818:Animals; D001341:Autonomic Nervous System / Q000378:metabolism*; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology; D002320:Cardiovascular Physiological Phenomena; D004357:Drug Synergism; D019004:Galanin / Q000378:metabolism* / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D009434:Neural Pathways / Q000378:metabolism; D009478:Neuropeptide Y / Q000819:agonists / Q000031:analogs & derivatives / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D044088:Receptors, Galanin / Q000819:agonists / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000819:agonists / Q000378:metabolism*; D017552:Solitary Nucleus / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D009478:Neuropeptide Y; D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D044088:Receptors, Galanin; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor; C095889:neuropeptide Y2 receptor; C074069:galanin-(1-13)-bradykinin-(2-9)-amide; D019004:Galanin; D001920:Bradykinin