Overexpression of corticotropin-releasing hormone in transgenic mice and chronic stress-like autonomic and physiological alterations.

To gain a greater insight into the relationship between hyperactivity of the corticotropin-releasing hormone (CRH) system and autonomic and physiological changes associated with chronic stress, we developed a transgenic mouse model of central CRH overproduction. The extent of central and peripheral CRH overexpression, and the amount of bioactive CRH in the hypothalamus were determined in two lines of CRH-overexpressing (CRH-OE) mice. Furthermore, 24 h patterns of body temperature, heart rate, and activity were assessed using radiotelemetry, as well as cumulative water and food consumption and body weight gain over a 7-day period.

Autonomic changes associated with enhanced anxiety in 5-HT(1A) receptor knockout mice.

5-HT(1A) receptor knockout (KO) mice have been described as more anxious in various anxiety paradigms. Because anxiety is often associated with autonomic changes like elevated body temperature and tachycardia, radiotelemetry was used to study these parameters in wild type (WT) and KO mice in stress-/anxiety-related paradigms. Basal body temperature (BT), heart rate (HR), and their diurnal rhythmicity did not differ between well-adapted WT and KO mice.

Reduced startle reactivity and plasticity in transgenic mice overexpressing corticotropin-releasing hormone.

Background: Corticotropin-releasing hormone (CRH) hyperactivity in transgenic mice overexpressing CRH in the brain (CRH-OE(2122)) appears to be associated with chronic stress-like alterations, including increased CRH content in the hypothalamus, changes in hypothalamus-pituitary-adrenal axis regulation, and increased heart rate and body temperature. In the present study, we investigated if sensory information processing of startling auditory stimuli was affected in CRH-OE(2122) mice.

Methods: CRH-OE(2122) mice (on C57BL/6J background) were subjected to a number of procedures probing sensory information processing mechanisms, including the acoustic startle response, habituation, and prepulse inhibition of startle.

5-HT(1B) receptor knockout mice show no adaptive changes in 5-HT(1A) receptor function as measured telemetrically on body temperature and heart rate responses.

Two presynaptic receptors play an important role in the regulation of serotonergic neurotransmission, i.e., the 5-HT(1A) and 5-HT(1B) receptor.

Two-lever drug-drug discrimination with the 5-HT1 receptor agonists flesinoxan and eltoprazine.

Previous drug discrimination studies with the 5-HT1 receptor agonists flesinoxan and eltoprazine showed a clear 5-HT1A receptor-mediated effect for flesinoxan and the involvement of both 5-HT1A and 5-HT1B receptors in eltoprazine. However, there was no clear antagonism of eltoprazine's cue, possibly due to the compound nature of the eltoprazine stimulus. In the present experiments, in order to create a specific 5-HT1A vs.