Hemodynamic variations of cold-induced vasooscillations on human finger，ra bbit ear and rat tail

:C old-induced vasooscillation has been studied in the rabbit ear，ra t tail and human finger. This oscillation was attributed to opening of arterio-venous anastomoses (A V A) caused by exposure to cold. Since hemodynamic variations among those three species were observed by laser-Doppler blood flow meter measurement at O\u27C local cold exposure，th e blood flow changes were compared，1. Blood flow changes for 5 min after immersion in 0 \u27C.1n the rabbit ears，in creases fromcontrol values of blood flow by cooling were seen in four of nine cases，decreases were in four and no change in one. 1n rat tails，in creases of blood flow by cooling were seen infive of eleven，d ecreases were in three，a nd no changes were in three. The blood flow in human fingers，however，de creased in all nine cases by the O\u27C exposure.11. Openings of AVA at two 1 cm -interval points by O\u27C exposureSyntonic openings of A V A were not observed at two close points in rabbit earsand rat tails. 1ncrease oftemperature did not follow the AV A opening. 1n human fingers，h owever，o penings of AVA occurredsimultaneously at two close points. The local blood temperature was raised with the flow increase induced by AVA openin