Gastric pathology produced by hypothalamic lesions in rats

Weight loss in rats following lateral hypothalamic or thalamic lesions

“…When comparisons are made with lesion control groups, the trend is quite different. Only one study reported positive results (Lindholm et al, 1975), and we failed to replicate this result in the present series of experiments. It is also apparent from inspection of Table 1 that lesion coordinates and parameters, and weight and sex of rat, are uncontrolled variables across experiments; the importance of these variables cannot be determined due to the paucity of reported data.…”

“…Moreover, only two experiments investigating excessive weight loss have compared the effects of LH lesions with the effects of control lesions rather than unoperated controls or sham-operated controls. These two experiments Yielded conflicting results: Lindholm et al (1975) reported excessive weight losses of rats with LH lesions compared with control thalamic lesions, while Levine and Schwartzbaum (1973) reported no excessive weight loss when rats with LH lesions were compared with rats sustaining entopeduncular lesions.From the foregoing, it is apparent that excessive weight loss in LH rats is not well established when comparisons are made with a lesion control group rather than a sham-operate or unoperated control group. This, in turn, leads to two reasonable postulates: First, excessive weight loss in rats sustaining LH lesions may not be an effect specific to LH lesion, and secondly, the fact that excessive weight loss is sometimes attributed to metabolic disorders, sometimes to excess urinary excretion, and sometimes to locomotor hyperactivity may reflect only that most investigators measure only two variables, 325…”

“…Moreover, only two experiments investigating excessive weight loss have compared the effects of LH lesions with the effects of control lesions rather than unoperated controls or sham-operated controls. These two experiments Yielded conflicting results: Lindholm et al (1975) reported excessive weight losses of rats with LH lesions compared with control thalamic lesions, while Levine and Schwartzbaum (1973) reported no excessive weight loss when rats with LH lesions were compared with rats sustaining entopeduncular lesions.…”

“…This is a critical point, since we (Lindholm et al, 1975) previously reported that LH lesions do produce excessive weight loss when compared with control thalamic lesions. The Lindholm et al experiment and the present one were highly similar in many important ways: The same experimenter performed all surgerY, all apparatus and equipment were the same, the strain of rat was the same,and lesion coordinates and parameters were the same.…”

“…Previous researchers have reported that, during this period, rats with LH lesions lose more weight than foodand water-deprived unoperated or sham-operated controls (Glick & Greenstein, 1972;Lindholm, Shumway, Grijalva, Schallert, & Ruppel, 1975;Montemurro & Stevenson, 1957;Morgane, 1961;Morrison, 1968;Stevenson & Montemurro, 1963). The excessive weight loss ("excessive" weight loss will be used consistently in this report to denote weight loss greater than can be accounted for by the total absence of food and water intake), when found, has been used as evidence to support claims of abnormally high metabolic rates (Morgane, 1961;Morrison, 1968;Stevenson & Montemurro, 1963), excessive urinary excretion (Crow, 1962; Dorn & Rothballer, 1968; O'Kelley & Hatton, 1969), and locomotor hyperactivity (Epstein, 1971;Morrison, 1968).…”