Substance P and calcitonin gene-related peptide in the chicken skin: distribution and cardiovascular effects.
A short vasodilatation but no plasma extravasation could be induced by antidromic stimulation of peripheral nerves in the chicken skin. Since in mammalian species the sensory neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) are involved in this mechanism, the distribution and the cardiovascular effect of these peptides were investigated in the chicken. In the skin, SP- and CGRP-immunoreactivity was found co-localized in the epidermis and dermis. On blood vessels, however, SP positive but CGRP negative nerve rfibres were observed. Systemic (i.v.) and local close arterial injection of SP produced dose-dependent cutaneous vasodilatation with threshold doses of 6.5 pmol/kg or 1 pmol, respectively. Neurokinin A and acetylcholine were about 20 to 50-fold less effective, when injected close arterially. Systemic injection of SP (5-1800 pmol/kg) dose-dependently evoked a short fall in blood pressure which was followed by a longer lasting pressor response. CGRP up to 800 pmol/kg did not change blood pressure but produced a pronounced tachycardia. Close arterial injection of CGRP resulted in variable bi- or triphasic vascular responses which consisted of vasodilatations and also vasoconstriction with thresholds between 0.25 and 65 pmol. The data also indicate that in the chicken, SP, and to a lesser extent CGRP, can be involved in antidromic vasodilatation.
Sann
H
H
Max-Planck-Institut für physiologische, Bad Nauheim, Germany. hsann@physiology.thohannover.de
Friedrich
R
R
Pierau
F K
FK
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007150:Immunohistochemistry; D007261:Infusions, Intra-Arterial; D007275:Injections, Intravenous; D017078:Laser-Doppler Flowmetry; D008297:Male; D015288:Neurokinin A / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012867:Skin / Q000098:blood supply / Q000737:chemistry* / Q000294:innervation; D013373:Substance P / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
D013373:Substance P; D015288:Neurokinin A; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine