Flow stimulates nitric oxide release in guinea pig heart: role of stretch-activated ion channels.
Blood flow regulates vessel tone triggering the release of nitric oxide; however, the mechanism involved in this phenomenon is unknown. We investigated whether coronary flow induces nitric oxide release in the isolated perfused guinea pig heart and the role of the stretch-activated ion channels in the effect of flow. We used gadolinium (3 microM) in order to block these channels, and estimated nitric oxide release by an oxyhemoglobin method. The results have shown a flow-dependent stimulation of nitric oxide release (fivefold increase at perfusion flow of 25 ml/min). Gadolinium inhibited this effect in a dose-dependent fashion. Acetylcholine was able to stimulate nitric oxide release in presence of gadolinium. We concluded that coronary flow stimulates nitric oxide release in the guinea pig heart. Stretch-activated ion channels mediate this effect. Acetylcholine and flow stimulate nitric oxide release by different mechanisms of action.
Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina-IPN, México D.F., 11340, Mexico. suarezjor@netscape.net
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J
Suárez
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C
Torres
L
L
Sánchez
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L
del Valle
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G
Pastelín
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005682:Gadolinium / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000378:metabolism; D014655:Vascular Resistance / Q000187:drug effects
D007473:Ion Channels; D010108:Oxyhemoglobins; D009569:Nitric Oxide; D005682:Gadolinium; D000109:Acetylcholine