Hormones and behavior
-
Hormones and behavior · Jun 2000
Differential distribution and regulation of OX1 and OX2 orexin/hypocretin receptor messenger RNA in the brain upon fasting.
To further understand the functions of the orexin/hypocretin system, we examined the expression and regulation of the orexin/hypocretin receptor (OX1R and OX2R) mRNA in the brain by using quantitative in situ hybridization. Expression of OX1R and OX2R mRNA exhibited distinct distribution patterns. Within the hypothalamus, expression for the OX1R mRNA was largely restricted in the ventromedial (VMH) and dorsomedial hypothalamic nuclei, while high levels of OX2R mRNA were contained in the paraventricular nucleus, VMH, and arcuate nucleus as well as in mammilary nuclei. ⋯ An initial decrease (14 h) and a subsequent increase (20 h) in OX1R mRNA levels after fasting were observed in the dorsomedial hypothalamic nucleus and lateral division of amygdala. Levels of OX2R mRNA were augmented in the arcuate nucleus, but remained unchanged in the dorsomedial hypothalamic nucleus, paraventricular hypothalamic nucleus, and amygdala following fasting. The time-dependent and region-specific regulatory patterns of OX1R and OX2R suggest that they may participate in distinct neural circuits under the condition of food deprivation.
-
Hormones and behavior · Apr 1999
Self-injurious behavior is decreased by cyproterone acetate in adult male rhesus (Macaca mulatta).
Self-injurious behavior (SIB) presents a serious problem in laboratory macaques that cannot be socially housed for scientific reasons and among institutionalized children and adults where it is often associated with different forms of brain dysfunction. We have experienced limited success in reducing SIB in macaques by enhancing their environment with enrichment devices. Psychotropic drugs also help, but problems are associated with their use. ⋯ We hypothesized that the progestin activity of CA represses the hypothalamic gonadal axis and decreases testosterone, which in turn decreases SIB. In addition, we speculate that the decrease in 5HIAA and HVA in CSF may have been caused by progestins decreasing the activity of MAO. Therefore, the reduction of SIB may also be related to an increase in the availability of active monoamines in the CNS.
-
Hormones and behavior · Mar 1996
Allopregnanolone (THP) mediates anesthetic effects of progesterone in rat brain.
Intravenous infusion of the progesterone or that of progesterone 5 alpha-reduced metabolite, 3 alpha-hydroxy-5 alpha-pregnan-20-one (THP), induces the loss of righting reflex in freely moving rats at the doses of 49 +/- 15 mg/kg or 5.6 +/- 2.2 mg/kg, respectively. The recovery time of righting reflex was 71 +/- 12 min and 21 +/- 5 min for progesterone and THP, respectively. The time course of brain concentrations of THP, but not that of progesterone, correlated with the loss and the recovery of righting reflex. ⋯ Following progesterone infusion brain level of THP in SKF 105111 pretreated rats was 12% that of vehicle-treated control, and the level of progesterone was 160%. No effect of SKF 105111 on brain THP level was detected in animals infused with THP. These results demonstrate that anesthetic effect of progesterone is mediated through its conversion to THP and support the hypothesis that endogenous metabolites of progesterone may be involved in the regulation of behavior in rats.
-
Hormones and behavior · Mar 1994
Regulation of territorial behavior in the sedentary song sparrow, Melospiza melodia morphna.
Male song sparrows (Melospiza melodia morphna) of western Washington State show year-round territoriality. Although territorial aggression during the breeding season was accompanied by high circulating levels of luteinizing hormone (LH) and testosterone (T), similar aggression in the non-breeding season occurred when gonadal hormone levels were basal. Experimental removal of territorial males in autumn resulted in new males taking over the territory within a few days. ⋯ In contrast, males exposed to STI in autumn showed a strong aggressive response during the challenge, but then territorial aggression abated rapidly when the stimuli were withdrawn. Implants of T into males in autumn reinstated the high level of aggression after withdrawal of STI in a manner similar to that seen during the breeding season. These data suggest that in M. m. morphna T does not activate territorial aggression per se, but may increase the intensity of an aggressive response to STI, and persistence of the behavior after STI is withdrawn.