Effects of indomethacin on cerebrovascular response to hypercapnea and hypocapnea in breath-hold diving and obstructive sleep apnea.
We tested whether breath hold divers (BHD) and obstructive sleep apnea (OSA) subjects had similar middle cerebral artery velocity (MCAV) responses to hypercapnea and hypocapnea. We analyzed changes in MCAV (cm/s) in response to hypocapnea and hyperoxic hypercapnea during placebo or after 90 min of oral indomethacin (100 mg) in BHD (N=7) and OSA (N=7). During control hypercapnea MCAV increased for 54.4% in BHD and 48.4% in OSA. Indomethacin blunted the MCAV increase in response to hypercapnea in BHD (P=0.02), but not in OSA. Indomethacin attenuated the mean arterial pressure response in BHD, but not in OSA. The blunted MCAV responses to hypercapnea with indomethacin in BHD, but not in OSA patients suggests that (a) the normal contribution of local vasodilating mechanisms to the cerebrovascular responses to hypercapnea is absent in OSA patients and (b) exposure to chronic/repeated apneas is not causal per se in limiting the contribution of vasodilating mechanisms to the cerebrovascular responses to hypercapnea in OSA.
Ivancev
Vladimir
V
Department of Physiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia.
Bakovic
Darija
D
Obad
Ante
A
Breskovic
Toni
T
Palada
Ivan
I
Joyner
Michael J
MJ
Dujic
Zeljko
Z
D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002317:Cardiovascular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D018592:Cross-Over Studies; D004242:Diving; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology*; D016857:Hypocapnia / Q000503:physiopathology*; D007213:Indomethacin / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D015656:Respiratory Mechanics / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000188:drug therapy / Q000503:physiopathology*
D002317:Cardiovascular Agents; D007213:Indomethacin