Role of mast cell chymase in angiotensin-induced vascular contraction of hamster cheek pouch microvessels.
We investigated the contribution of chymase-dependent conversion of angiotensin I to angiotensin II in hamster cheek pouch. To investigate the converting activities in intact tissues, angiotensin I or II was applied to microvessels of the intact cheek pouch, and the vascular contractile response was recorded. Angiotensin I or angiotensin II (20 nM) induced a rapid contraction of arterioles, irrespective of their diameter. In the presence of I mM captopril, there was no contraction in response to angiotensin I in arterioles < 25 microm in diameter, whereas contraction was still observed in larger arterioles. Chymostatin (100 microM) treatment also reduced the response to angiotensin I in arterioles > 40 microm in diameter. Treatment with 1 mM captopril and 100 microM chymostatin resulted in the loss of response to angiotensin I, but not to angiotensin II, in all arterioles. Treatment of microvessels with 100 microg/ml compound 48/80 enhanced angiotensin I-induced vascular contraction response, suggesting the significance of mast cells as a source of cheek pouch chymase.
Katada
J
J
Life Science Research Center, Advanced Technology Research Laboratories, Kawasaki, Japan. katada@kt.rim.or.jp
Muramatsu
M
M
Hayashi
M
M
Hattori
M
M
D000803:Angiotensin I / Q000378:metabolism* / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D053818:Chymases; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D008407:Mast Cells / Q000201:enzymology* / Q000473:pathology; D008833:Microcirculation / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009842:Oligopeptides / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000502:physiology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D009842:Oligopeptides; D015842:Serine Proteinase Inhibitors; D000804:Angiotensin II; D003189:p-Methoxy-N-methylphenethylamine; D000803:Angiotensin I; C002101:chymostatin; D002216:Captopril; D012697:Serine Endopeptidases; D053818:Chymases