HIGH-VOLTAGE PULSED CURRENT - ITS INFLUENCE ON DIAMETERS OF HISTAMINE-DILATED ARTERIOLES IN HAMSTER-CHEEK POUCHES

Results from five independent studies from our laboratory indicate tha t cathodal high-voltage pulsed current (HVPC) significantly curbs post traumatic edema formation in several animal models, Conversely, anodal HVPC did not curb edema formation, The mechanism hy which HVPC reduce s edema formation is unknown, We hypothesize that HVPC causes a decrea se in local blood flow by active vasoconstriction of arterioles, Becau se we had previously observed positive effects with cathodal HVPC but not anodal HVPC, we further hypothesized that cathodal but not anodal HVPC would reduce diameters of histamine-dilated arterioles, Changes i n diameters of resistance arterioles (5 to 30 mu m internal diameter) were measured directly in cheek pouches of anesthetized hamsters, usin g in vivo video microscopy, Three minutes after superfusion with the i nflammatory mediator (histamine) was begun, sensory-level HVPC at 120p ps was applied concurrently for 30 minutes, Five animals received cath odal HVPC and five received anodal HVPC, Pour other animals received 3 0-minute treatments of both cathodal and anodal HVPC in random order, Three control animals received histamine without HVPC for 30 minutes, Diameter changes of one arteriole from each cheek pouch was measured e very 20 seconds throughout the treatment period, One-way analysis of v ariance (ANOVA) with repeated measures showed that diameters of histam ine-dilated controls varied little over 30 minutes, and that adding ca thodal HVPC did not significantly alter diameters of arterioles superf used with histamine, However, applying anodal HVPC to histamine-dilate d arterioles significantly reduced arteriolar diameters, These results do not support the hypothesis that cathodal HVPC curbs edema formatio n by increasing arteriolar tone in the injured area. (C) 1995 by the A merican Congress of Rehabilitation Medicine and the American Academy o f Physical Medicine and Rehabilitation