Emergence during development of the white-adipocyte cell phenotype is independent of the brown-adipocyte cell phenotype.

In mammals, two types of adipose tissue are present, brown and white. They develop sequentially, as brown fat occurs during late gestation whereas white fat grows mainly after birth. However, both tissues have been shown to have great plasticity.

Conditional coupling of striatal dopamine D1 receptor to transcription factors: ontogenic and regional differences in CREB activation.

The coupling of striatal dopamine D1 receptors to c-fos transcription exhibit all-or-none regional and ontogenic differences: the D1 agonist SKF 38393 fails to induce c-fos expression in the striatum, except during the early postnatal period in the striosomes, or in the caudal extremity of the striatum in adult animals. In an attempt to better delineate the mechanism responsible for interrupting or enabling this conditional coupling of D1 receptors to c-fos transcription we have examined, through immunocytochemistry and gel shift assay, the activation of the cyclic AMP-response element binding protein (CREB) transcription factor in response to the D1 agonist in the murine striatum. Phosphorylated-CREB (P-CREB) immunoreactivity in response to the dopamine D1 agonist (+/-)SKF 38393 (15 mg/kg, i.

Transient neonatal elevation in hypothalamic estrogen receptor mRNA in prenatally-stressed male rats.

Prenatal stress in rats has been found to alter the sexual dimorphism of brain structures and the sexual behavior of male offspring, pointing to an impaired masculinization of the brain during the perinatal period of brain sexual differentiation. Masculinization of the brain depends on the presence during this critical period of three main elements: adequate levels of testosterone, aromatase activity (locally converting testosterone to estradiol), and brain estrogen receptor (ER) density. In the present study, we measured by reverse transcription-polymerase chain reaction (RT-PCR) the levels of ER messenger RNA (mRNA) expression in the hypothalamus of either prenatally-stressed or control male rats at postnatal (P) days 3, 12 and 90.

Involvement of the caudal striatum in auditory processing: c-fos response to cortical application of picrotoxin and to auditory stimulation.

The topographical organization of corticostriatal connections have been postulated to follow a longitudinal pattern, each cortical area projecting on a longitudinal strip stretching along the whole rostro-caudal axis of the striatum. However, compared to the rostral striatal region, the caudal striatum exhibits distinct features in terms of connectivity and neuronal phenotype. The induction of c-fos expression in the striatum by cortical activation or sensory stimulation may throw more light on these functional corticostriatal relationships.

Postnatal ontogeny of dopamine D3 receptors in the mouse brain: autoradiographic evidence for a transient cortical expression.

The expression of dopamine D3 receptors is relatively low in the adult brain and is mainly restricted to the limbic region. We studied here the postnatal development of these receptors in the mouse brain by quantitative autoradiography using [3H](+/-)-7-OH-DPAT as ligand. In all brain regions examined, there was a progressive increase in D3 receptor protein expression from birth to the weaning period, a pattern reminiscent of that of dopamine D2 rather than D1 receptors.