Reactions of Wild and Albino Mice in Response to Forced Swimming.

Abstract

Enforced swimming of animals has been some experiments, colonic temperatures were utilized by many investigators as a method obtained continuously while the animals of inducing and evaluating physiological and swam, thus weighting the animal by an addipsychological stress. However, the time re-tional 2 g. The mice utilized to obtain these quired to produce a state of exhaustion has cooling curves were not utilized in any other shown considerable variation not only among experiments. Cooling curves were obtained individual animals, but in the mean times from 2 mice of each type while swimming reported by various investigators(4,5,8,10). at water temperatures of 15, 20 and 28°C. Some of the variability reported could have Since some investigators swam animals in been due to variations in water temperature groups, a few experiments were conducted ( l ) , in nutritional state of the animals( lo), comparing the 2 strains of mice under similar in the criteria for exhaustion or in species conditions. differences. Griffiths (6) found that domestic Swimming times were measured to the rats swam for a longer period of time than nearest second by means of a stop watch. 2 strains of wild rats, except when treated Initially, the end point was considered to with a drug (stilazine) or had their vibrissae be the onset of disorientation, the typical removed. Richter (9) has also observed dif-criteria utilized by most investigators. Howferences between wild and domestic rats and ever, this proved to be unsatisfactory and has noted that trimming of whiskers resulted a more precise end point, i.e., the time at in a quick death for all wild rats thus treated which the animal was unable to return to prior to enforced swimming. Since many the surface of the water, was finally employed. swimming experiments are conducted on mice it appeared that a comparison of the responses of wild and domestic mice would be of value, especially if more objective methods of evaluating final exhaustion were employed.Methods. A plastic cylinder, 26.5 cm d i m . with a water depth of 24 cm was utilized for the swimming tests. A wetting agent was added to the water and air was bubbled through the water column. Water temperatures of 15, 20, 28, 37, or 42OC were maintained within * 0.2"C and continuously monitored. This temperature as well as the colonic temperatures of the mice were measured utilizing thermistors and a Yellow Springs bridge. The thermistor probe was placed to a depth of 3.5-4 cm in the colon. The majority of measurements of colonic temperature were obtained at the point of exhaustion or termination of the swim. In

Two water environment adaptation models enhance motor behavior and improve the success of the lactate minimum test in swimming rats

“…Sub AnT and Supra AnT ) performed more incremental stages in the lactate minimum test, resulting in an increased lactate minimum success rate after the water environment adaptation period. Although reports have shown that luminosity, time of day and water temperature have an effect on swimming rats 2,3,4,5 , we presented novel data regarding the water environment adaptation period influencing the climbing-swimming pattern prevalence. The fact that studies have not been concerned with the proper water environment adaptation raises questions about its importance on experimental procedures involving swimming rats.…”

“…Although rodents have a recognized, innate swimming ability 1 , studies have demonstrated that luminosity 2 , water temperature 3,4 and the time of day 5 may influence swimming performance in these animals. Furthermore, a discussion about the water environment adaptation was already initiated 6 , but its relevance remains speculative and untested.…”

A reconsideration of psychological precursors of sudden death in infrahuman animals.

“…We found that at higher water pressures (keeping water temperature constant at a point of thermoneutrality for the rat-34° C), no rats survived because of an inability to keep their nostrils above the surface (Hughes et al, in press). The jet pressure, like the addition of weight used in most swimming endurance studies, functions to increase the work and energy needed to remain afloat (e.g., Foss & Horvath, 1965;McArdle, 1967;Werboff, Haggett, & Anderson, 1967). As with the use of weights, subtle changes in jet pressure have a drastic effect on swimming performance and suggest a partial explanation for survival differences in recent studies (Rossellini et al 1976).…”