Adrenergic modulation of calcitonin gene-related peptide (CGRP)-containing nerve-mediated vasodilation in the rat mesenteric resistance vessel.
Pharmacological studies showed that periarterial nerve stimulation (PNS) of the perfused rat mesenteric vascular bed contracted with endothelin, a vasoconstrictor peptide, in the presence of prazosin (alpha 1-adrenoceptor antagonist) produced a frequency-dependent neurogenic vasodilation when the adrenergic neurotransmission was blocked by the adrenergic neuron blocker, guanethidine. The PNS-evoked vasodilation was attenuated by tetrodotoxin and capsaicin treatment, and was also inhibited when the adrenergic neurotransmitter (norepinephrine; NE) release was left intact in the absence of guanethidine. However, in the combined presence of an alpha 2-adrenoceptor antagonist (yohimbine) and prazosin, PNS caused a marked neurogenic vasodilation even when the neuronal release of NE was left intact. These results suggest that NE released from adrenergic nerves regulates the release of a vasodilator substance, CGRP, through activation of alpha 2-adrenoceptors on CGRP-containing vasodilator nerves.
Kawasaki
H
H
Department of Pharmacology, Miyazaki Medical College, Japan.
Nuki
C
C
Saito
A
A
Takasaki
K
K
D000320:Adrenergic Fibers / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D013152:Splanchnic Circulation / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*
D011942:Receptors, Adrenergic, alpha; D015740:Calcitonin Gene-Related Peptide; D009638:Norepinephrine; D011224:Prazosin