Increases in Plasma Dihydroxyphenylacetic Acid Levels in Decapitated Mice after Exposure to Various Stresses.

Abstract

This study investigated changes in plasma levels of the dopamine metabolite dihydroxyphenylacetic acid (DOPAC) in decapitated mice in response to the variable stresses of restraint, restraint and water immersion, and foot shock. DOPAC levels, but not norepinephrine (NE) and epinephrine (EPI) levels, increased upon exposure to these stresses. Plasma DOPAC levels measured using the decapitation method in rats were then compared with those measured using the catheter method. The NE and EPI levels in plasma measured using the decapitation method were much higher than those using the catheter method under basal conditions. In contrast, differences in the levels of DOPAC in plasma were smaller than those of NE and EPI under basal conditions using in both methods; furthermore parallel changes in plasma DOPAC levels occurred during restraint and water immersion stresses. These results indicate that the plasma DOPAC levels measured in mice using the decapitation method were clearly increased by the different stresses. Furthermore, in rats there were correlations between the decapitation and catheter methods for plasma levels of DOPAC. Thus the change in plasma DOPAC levels measured using the decapitation method is a good indicator of stress responses involving sympathoneural activity.

Dynamic Responses to Acute Heat Stress between 34 .DEG.C. and 38.5 .DEG.C., and Characteristics of Heat Stress Response in Mice

“…It is known that plasma DA and DOPAC levels depend on the activity of tyrosine hydroxylation in sympathetic neurons. 26,27) Clearly, heat stress would have few effects on the sympathetic nerves. On the other hand, it is reported that heat stress using severe conditions, such as 42°C, increased plasma NE and epinephrine levels in rats.…”

“…Measurements of Plasma Dopamine (DA) and Dihydroxyphenylacetic Acid (DOPAC) Levels Mice were exposed to 37°C 85% RH or RWI for 10, 20, 40, 80 and 160 min. The concentrations of DA and DOPAC in the plasma were assayed using HPLC with electrochemical detection (ECD) after batch alumina extraction as previously described 26) with the following modifications. For the HPLC, the separation column was a Biophase ODS IV (3 mm, 4ϫ110 mm, BAS, Tokyo, Japan) and the mobile phase consisted of 50 mM citrate buffer, pH 3.2, containing 8% acetonitrile, 1 mM EDTA and 0.3 mM sodium octylsulfate.…”

“…In addition, plasma catecholamine and metabolite levels generally increased in response to stress. Plasma dopamine and dihydroxyphenylacetic acid levels, which depend on sympathoneural activity, 26,27) were also measured during heat stress in this study.…”

Psychophysiological stress‐regulated gene expression in mice

“…Studies on such responses have been conducted using cultured cells or whole organisms, including a shift of temperature, exposure to chemicals, irradiation and lack of nutrients. Here, we report the responses to stress occurring in the brain of mice subjected to cage‐restraint and water‐immersion, which are methods that have been used widely in psychophysiological analyses [1,2]. Recently, Hayashi et al [3] reported that diazepam, an anti‐depressant drug, blocked the induction of a stress‐response marker in mouse brain under psychophysiological stress, suggesting a psychological component of the stress.…”