Tone-dependent vasodilator responses to proadrenomedullin NH2-terminal 20 peptide in the hindquarters vascular bed of the rat.
Responses to proadrenomedullin NH2-terminal 20 peptide (PAMP) were investigated in the systemic and hindquarters vascular bed of the rat. Intravenous injections of PAMP and adrenomedullin (ADM) produced dose-related decreases in systemic arterial and hindquarters perfusion pressure, which were not altered by alpha-receptor or adrenergic nerve terminal blocking agents. PAMP was 100-fold less potent than ADM, and hindquarters vasodilator responses to both peptides were similar in innervated and denervated preparations. When baseline tone was increased with phenylephrine and U46619 or decreased with sodium nitroprusside, vasodilator responses to PAMP and ADM were correlated with the basal level of tone, suggesting that responses to both peptides are dependent on the baseline level of vasoconstrictor tone in the hindquarters vascular bed of the rat.
Champion
H C
HC
Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
Czapla
M A
MA
Friedman
D E
DE
Lambert
D G
DG
Murphy
W A
WA
Coy
D H
DH
Kadowitz
P J
PJ
D053607:Adrenomedullin; D000818:Animals; D004353:Drug Evaluation, Preclinical; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000294:innervation; D006614:Hindlimb / Q000098:blood supply* / Q000294:innervation; D009129:Muscle Tonus / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D010446:Peptide Fragments; D010455:Peptides; D011506:Proteins; D014665:Vasodilator Agents; D053607:Adrenomedullin; D009638:Norepinephrine