Molecules acting on receptor level at weaning, durably influence liver glucocorticoid receptors.

In the experiments the effect of late hormonal imprinting to the liver glucocorticoid receptors were studied. Three-week-old (weanling) female rats were treated with five molecules acting at receptor level and four weeks later receptor kinetic analysis was done on liver glucocorticoid receptors. The tricyclic antidepressant, histamine and serotonin receptor blocker mianserin positively influenced receptor density and negatively receptor affinity.

Effect of treatment at weaning with the serotonin antagonist mianserin on the brain serotonin and cerebrospinal fluid nocistatin level of adult female rats: a case of late imprinting.

Four weeks old (weanling) female rats were treated with the tricyclic antidepressant and histamine/serotonin receptor blocker mianserin for studying its faulty hormonal imprinting effect. Measurements were done four months later. Brain serotonin levels significantly decreased in four regions (hippocampus, hypothalamus, striatum and brainstem), without any change in the cortex.

Impact of single neonatal serotonin treatment (hormonal imprinting) on the brain serotonin content and sexual behavior of adult rats.

Hormonal imprinting takes place perinatally at the first encounter between the developing receptor and its target hormone. As a consequence of imprinting the receptor accomplishes its maturation and reaches the binding capacity characteristic to the adult age. In the excess of target hormone or presence of molecules similar to the target hormone, which are able to bind to the unmatured receptors, faulty imprinting develops with life-long consequences.

H1-receptor blocker antihistamine, terfenadine durably influences the glucocorticoid receptor, and lymphocyte histamine content of weanling rats.

Hormonal imprinting takes place perinatally when a hormone and its maturing target receptor meet. As a consequence of imprinting the receptor accomplishes its maturation reaching the binding capacity characteristic to the adult age. In this critical period the presence of foreign molecules which are able to bind to the receptor can cause faulty imprinting with life-long consequences.

Effect of neonatal beta-endorphin imprinting on sexual behavior and brain serotonin level in adult rats.

A single dose (3 microg) beta-endorphin was administered to newborn female and male rats (hormonal imprinting). In adult age (at 5 months) sexual behavior, steroid hormone binding capacity and brain serotonin content was studied. Females' sexual activity (lordosis quotient) significantly decreased and more animals protested against mounting (ratio of kicking and crying 21/24 vs.