Effect of intracarotid administration of 6-aminonicotinamide on cerebral blood flow in cats.
OBJECTIVE
We evaluated the effects of an adenosine triphosphate blocker, 6-aminonicotinamide (6-ANA), on the cerebral blood flow (CBF), cerebral metabolism, and electroencephalogram of cats.


METHODS
Catheters were inserted into the common carotid artery of 16 adult cats anesthetized with ketamine via the lingual artery. We measured CBF in the infused area by the inhaled hydrogen gas clearance method and analyzed the electroencephalogram frequency. Cerebral metabolism was estimated by oxygen extraction (vol/%) and glucose utilization (millimoles) using data arterial (aorta) and sagittal sinus blood samplings. A solution of 6-ANA (6.0 mg/mL) (n = 8) or saline (n = 8) was infused via catheter at 2.0 mL/min for 3 minutes followed by a 60-minute observation of CBF, cerebral metabolism, vascular resistance, and the electroencephalogram components, alpha-2 ratio [= alpha-2/(alpha-1+alpha-2)]. The effect of 6-ANA on capillaries was evaluated by extravasation of Evans blue dye and electron microscopic findings.


RESULTS
Moderate reductions in CBF, cerebral metabolism, and the alpha-2 ratio were observed during the infusion of 6-ANA versus saline infusion (P < .05 by paired t test and ANOVA). Vascular resistance was significantly increased (P < .05). No abnormalities were observed in the capillaries of the infused hemisphere.


CONCLUSIONS
Results indicated that 6-ANA produced a downregulation of cerebral blood flow in cats.
Kuchiwaki
H
H
Department of Neurosurgery, Nagoya University School of Medicine, Japan.
Inao
S
S
Yoshida
K
K
Sugita
K
K
D015120:6-Aminonicotinamide / Q000008:administration & dosage / Q000494:pharmacology*; D000513:Alpha Rhythm / Q000187:drug effects; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects; D001921:Brain / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D002196:Capillaries / Q000187:drug effects / Q000648:ultrastructure; D017536:Carotid Artery, Common; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D015536:Down-Regulation; D004569:Electroencephalography / Q000187:drug effects; D005070:Evans Blue; D005119:Extravasation of Diagnostic and Therapeutic Materials; D005260:Female; D005947:Glucose / Q000378:metabolism; D007269:Injections, Intra-Arterial; D008297:Male; D008854:Microscopy, Electron; D010101:Oxygen Consumption / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D015120:6-Aminonicotinamide; D005070:Evans Blue; D005947:Glucose