Increased histidine preference during specific alteration of rhythm of environmental temperature stress in rats.

Abstract

It has been reported that specific alteration of rhythm of environmental temperature (SART) stress induces various physiological changes. In this study, changes in taste preference during SART stress were investigated in rats. Rats were given free access to six amino acid solutions, saline, and water in a choice paradigm. During SART stress, daily food intake increased significantly by 50% whereas the rate of body weight gain decreased significantly to one third that observed during the prestress baseline period. In addition, consumption of histidine solution increased significantly, whereas intakes of water, monosodium glutamate, saline, glycine, arginine, lysine, and threonine were unaffected. Results suggest that a specific preference for histidine emerges during SART stress, which may be related to the stress-induced changes in the histamine turnover in the brain and peripheral tissues.

Effects of Repeated Cold Stress on Activity of Hypothalamic Neurons in Rats During Performance of Operant Licking Task

“…This interpretation is of interest when considering the functional implication of these two brain areas. For instance, hyperphagia is a unique characteristic of chronic cold stress including repeated cold stress (Bing et al 1998;Hata et al 1984aHata et al ,b, 1988aKondoh et al 1996;Leung and Horwitz 1976;Morrison 1981;Okano et al 1993;Snyder and Stricker 1985), which can be clearly distinguished from the anorexia induced by severe acute stress conditions (Morley and Levine 1982;Shimizu et al 1989). Consistent with the previous studies (Hata et al 1984a(Hata et al ,b, 1988aKondoh et al 1996;Okano et al 1993), in the present study we also observed an increase in food intake in the rats exposed to repeated cold stress.…”

“…For instance, hyperphagia is a unique characteristic of chronic cold stress including repeated cold stress (Bing et al 1998;Hata et al 1984aHata et al ,b, 1988aKondoh et al 1996;Leung and Horwitz 1976;Morrison 1981;Okano et al 1993;Snyder and Stricker 1985), which can be clearly distinguished from the anorexia induced by severe acute stress conditions (Morley and Levine 1982;Shimizu et al 1989). Consistent with the previous studies (Hata et al 1984a(Hata et al ,b, 1988aKondoh et al 1996;Okano et al 1993), in the present study we also observed an increase in food intake in the rats exposed to repeated cold stress. Previous behavioral and neurophysiological studies have suggested that the LHA and ventromedial hypothalamic nucleus (VMH, a part of the MHA defined in the present study) control feeding behavior in opposing manners; the LHA is thought to be a feeding center and the VMH together with the PVN are satiety centers (Delgado and Anand 1953;Leibowitz 1986;Oomura et al 1967Oomura et al , 1969Shimizu et al 1987;Smith 1956;Winn et al 1984).…”

“…The levels of histamine and histamine turnover in the hypothalamus change during cold stress (Taylor and Snyder 1971). We recently found that repeated cold stress induces a specific preference for histidine (Kondoh et al 1996). Therefore we originally predicted that repeated cold stress would change the proportion of differential neurons or increase the number of neurons that specifically respond to histidine solution and its associated CTS.…”

“…Repeated cold stress is a type of chronic cold stress in which environmental temperature changes rapidly and frequently several times within a day (Hata et al 1984a). Animals exposed to chronic cold stress display various abnormalities including hyperphagia, decrease in weight gain, hyperalgesia, low blood pressure, decreased acetylcholine (ACh) response in the isolated duodenum, suppression of antibody formation, hypersensitivity in the immediate immunoreaction, and alteration in hypothalamo-pituitary-adrenal and sympathoadrenal systems (Akana and Dallman 1997;Bing et al 1998;Fukuhara et al 1996a,b;Hanson et al 1996;Hata et al 1984aHata et al ,b, 1988aKawanishi et al 1997;Kondoh et al 1996;Kvetnansky et al 1995;Leung and Horwitz 1976;Morrison 1981;Namimatsu et al 1992;Okano et al 1993;Snyder and Stricker 1985).…”

“…Although some behavioral studies have reported that repeated cold stress produces abnormalities in food intake such as hyperphagia and a specific preference for histidine solution (Hata et al 1988;Kita et al 1979;Kondoh et al 1996), little is known, at neuronal level, as to how repeated cold stress affects the CNS that is involved in the control of food intake (such as the LHA, MHA, and paraventricular nucleus). In the present study, therefore we addressed this issue as the principal purpose, using the method described in the preceding text.…”