Learning-induced survival of new neurons depends on the cognitive status of aged rats.

Aging is accompanied by an alteration of spatial memory, which has been related to an alteration in hippocampal plasticity. Within the dentate gyrus, new neurons are generated throughout the entire life of an individual. This neurogenesis seems to play a role in hippocampal-mediated learning and learning-induced changes in neurogenesis have been proposed to be involved in memory.

Rat strain differences in peripheral and central serotonin transporter protein expression and function.

Female Fischer 344 (F344) rats have been shown to display increased serotonin transporter (5-HTT) gene expression in the dorsal raphe, compared to female Lewis (LEW) rats. Herein, we explored, by means of synaptosomal preparations and in vivo microdialysis, whether central, but also peripheral, 5-HTT protein expression/function differ between strains. Midbrain and hippocampal [3H]paroxetine binding at the 5-HTT and hippocampal [3H]serotonin (5-HT) reuptake were increased in male and female F344 rats, compared to their LEW counterparts, these strain differences being observed both in rats of commercial origin and in homebred rats.

Fox odour affects corticosterone release but not hippocampal serotonin reuptake and open field behaviour in rats.

Group-housed Sprague-Dawley (SD) rats exposed for 1 h to 2,5-dihydro-2,4,5-trimethylthiazoline (TMT, a component of fox feces) did not display changes in hippocampal serotonin (5-HT) metabolism and [3H]5-HT reuptake, compared to water or butyric acid. Such an observation extended to isolated SD and Fischer 344 rats. When group-housed SD rats were tested 1 week after a 1-h exposure to TMT, hippocampal 5-HT metabolism, [3H]5-HT reuptake, and [3H]paroxetine binding at the 5-HT transporter remained unchanged.

Influences of the corticotropic axis and sympathetic activity on neurochemical consequences of 3,4-methylenedioxymethamphetamine (MDMA) administration in Fischer 344 rats.

The respective influences of the corticotropic axis and sympathetic activity on 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) immediate effects on body temperature and long-term neurotoxicity, as assessed by decreases in hippocampal and striatal [(3)H]5-hydroxytryptamine ([(3)H]5-HT) reuptake, [(3)H]paroxetine binding at 5-HT transporters (5-HTT), and 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels, were examined in Fischer 344 rats. On each of the two injections of MDMA (5 or 10 mg/kg s.c.