Pmch expression during early development is critical for normal energy homeostasis.

Postnatal development and puberty are times of strong physical maturation and require large quantities of energy. The hypothalamic neuropeptide melanin-concentrating hormone (MCH) regulates nutrient intake and energy homeostasis, but the underlying mechanisms are not completely understood. Here we use a novel rat knockout model in which the MCH precursor Pmch has been inactivated to study the effects of loss of MCH on energy regulation in more detail.

Cocaine strongly reduces prepulse inhibition in apomorphine-susceptible rats, but not in apomorphine-unsusceptible rats: regulation by dopamine D2 receptors.

Dopaminergic agonists, such as apomorphine and amphetamine, have been shown to drastically reduce prepulse inhibition of the acoustic startle reflex. The effects of the indirect dopamine agonist cocaine on prepulse inhibition have only been described in a few reports and have yielded conflicting results, possibly due to individual differences within and between rat strains. In this study we therefore used apomorphine-susceptible and apomorphine-unsusceptible rats, as an animal model for individual differences, to study the effects of cocaine (20, 30 mg/kg i.

Differences in the cellular mechanism underlying the effects of amphetamine on prepulse inhibition in apomorphine-susceptible and apomorphine-unsusceptible rats.

Background: Amphetamine is often used to mimic certain aspects of schizophrenia in laboratory animals, such as a decreased prepulse inhibition.

Materials And Methods: Apomorphine-susceptible and apomorphine-unsusceptible rats represent a well-characterized animal model for individual differences in the sensitivity to dopaminergic drugs. Moreover, apomorphine-susceptible rats show a wide variety of schizophrenia-like abnormalities.

Individual differences in drug dependence in rats: the role of genetic factors and life events.

Drug dependence and addiction is a chronic mental illness that has far reaching consequences for society in terms of economic loss, health costs and judicial problems. A crucial question in drug addiction, is what factors are involved in its aetiology, and especially what mediates the shit from use to abuse. As in most other mental illnesses, addiction can best be described using the so-called three hit model, which states that a disease results from an interaction between genetic factors, early lie events and late environmental factors.

A single exposure to novelty differentially affects the accumbal dopaminergic system of apomorphine-susceptible and apomorphine-unsusceptible rats.

Individual differences in responses to mild, acute stressors in laboratory animals have commonly been observed in behavioural tests and at the level of hypothalamic-pituitary-adrenal axis responses. These differences are associated with dopamine transmission in the nucleus accumbens. Although the effect of mild stressors on dopamine transmission has been studied with microdialysis, it has not been studied at the level of the catecholaminergic network in the nucleus accumbens.

Apomorphine-susceptible rats and apomorphine-unsusceptible rats differ in the tyrosine hydroxylase-immunoreactive network in the nucleus accumbens core and shell.

Individual variability in behavioural responses to stressors such as novelty and drugs of abuse is a well-known phenomenon in both animals and man. These individual differences are largely associated with differences in dopamine transmission in mesolimbic areas such as the nucleus accumbens. Apomorphine-susceptible (APO-SUS) rats and apomorphine-unsusceptible (APO-UNSUS) rats serve as a valid animal model for individual differences and these two types of rat differ in a number of behavioural, physiological, endocrinological and pharmacological parameters.