Autoregulation in the middle meningeal artery.
In cats anesthetized with alpha-chloralose, autoregulation of blood flow (F) in the middle meningeal and common carotid arteries was assessed by bleeding and subsequently reinfusing the animals to achieve a 25% step reduction in mean arterial blood pressure (P), while maintaining the systolic blood pressure >80 mmHg. The integrity of autoregulation was assessed by calculating the gain factor Gf = 1 - [(deltaF/F)/(deltaP/P)]. Cats were examined intact, after hexamethonium (10 mg/kg), and after papaverine (6 mg/kg). Reduction of blood pressure of 25 to 60 mmHg produced equivalent drops in carotid blood flow (Gf = 0.041 +/- 0.34; mean +/- standard deviation, n = 12). There were only small changes in flow in the middle meningeal artery during this procedure (Gf = 0.91 +/- 0.29). Hexamethonium did not block autoregulation in the middle meningeal artery (Gf = 0.92 +/- 0.13, n = 4). However, papaverine almost completely abolished the ability of the artery to autoregulate (Gf = 0.10 +/- 0.16, n = 7). The results suggest that the middle meningeal artery possesses an ability similar to that of the cortical circulation to autoregulate its blood flow through intrinsic, non-neuronal mechanisms. This will have important implications for the study of disturbances of dural arterial control in migraine and other headaches.
Michalicek
J
J
Institute of Neurological Sciences, The Prince Henry and Prince of Wales Hospitals, University of New South Wales, Australia.
Gordon
V
V
Lambert
G
G
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries / Q000502:physiology; D002415:Cats; D018738:Hexamethonium / Q000494:pharmacology; D006706:Homeostasis / Q000187:drug effects; D007275:Injections, Intravenous; D008576:Meningeal Arteries / Q000187:drug effects / Q000502:physiology*; D010208:Papaverine / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects
D018738:Hexamethonium; D010208:Papaverine