G protein activation elicits cerebrovasodilation through interaction with K(ATP) and K(Ca) channels.
This study was designed to characterize the vascular activity of two activators of a pertussis toxin-sensitive G protein, mastoparan and mastoparan-7, on pial artery diameter and their interaction with the ATP sensitive K (K(ATP)) and calcium sensitive K (K(Ca)) channel in newborn pigs equipped with a closed cranial window. Mastoparan (10(-8), 10(-6) M) elicited pial artery dilation that was blunted by the K(ATP) channel antagonist glibenclamide (10(-6) M) and attenuated by the K(Ca) channel antagonist iberiotoxin (10(-7) M) (10+/-1 and 17+/-1 vs. 3+/-1 and 6+/-1 vs. 6+/-1 and 10+/-2% for mastoparan in the absence and presence of glibenclamide or iberiotoxin, respectively). Similar results were observed for mastoparan-7 but the inactive analogue mastoparan-17 had no effect on pial artery diameter. These data show that G protein activation elicits cerebrovasodilation through interaction with K(ATP) and K(Ca) channels.
Armstead
William M
WM
Department of Anesthesia, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA. armsteaw@mail.med.upenn.edu
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D005260:Female; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D005905:Glyburide / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D010455:Peptides / Q000494:pharmacology; D010841:Pia Mater / Q000098:blood supply / Q000187:drug effects / Q000502:physiology; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D034421:Sus scrofa; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014862:Wasp Venoms / Q000494:pharmacology
D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D024681:Potassium Channels, Calcium-Activated; D014862:Wasp Venoms; C037500:mastoparan; C064719:iberiotoxin; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins; D005905:Glyburide