Nicotinic excitation of serotonergic projections from dorsal raphe to the nucleus accumbens.

Tobacco use is a major public health problem, and although many smokers report that they want to quit, only a small percentage succeed. Side effects associated with nicotine withdrawal, including depression, anxiety, and restlessness, certainly contribute to the low success rate. The dorsal raphe nucleus (DRN) is a serotonergic center with many functions, including control of mood and emotional state.

Bupropion inhibits the cellular effects of nicotine in the ventral tegmental area.

Each year, tobacco use causes over 4 million deaths worldwide and billions of dollars are spent on treatment for tobacco-related illness. Bupropion, an atypical antidepressant, improves the rates of successful smoking cessation, however, the mechanisms by which bupropion reduces cigarette smoking and depression are unknown. Here we show that clinical concentrations of bupropion inhibit nicotine's stimulatory effects on brain reward areas.

Enhanced nicotinic receptor function and drug abuse vulnerability.

In animals and humans, vulnerability to drug abuse varies among individuals. Animals that display high activity levels in a novel environment are more likely to self-administer psychostimulant drugs, including nicotine, cocaine, amphetamine, and morphine. Recent reports from behavioral studies indicate that nicotinic acetylcholine receptor (nAChR) activity contributes to the rewarding effects of several different addictive drugs.

Growth plate senescence is associated with loss of DNA methylation.

The overall body size of vertebrates is primarily determined by longitudinal bone growth at the growth plate. With age, the growth plate undergoes programmed senescence, causing longitudinal bone growth to slow and eventually cease. Indirect evidence suggests that growth plate senescence occurs because stem-like cells in the growth plate resting zone have a finite proliferative capacity that is gradually exhausted.

Lack of telomere shortening with age in mouse resting zone chondrocytes.

Background And Aim: Telomeres are hexameric repeat sequences that flank eukaryotic chromosomes. The telomere hypothesis of cellular aging proposes that replication of normal somatic cells leads to progressive telomere shortening which induces replicative senescence. Previous studies suggest that growth plate chondrocytes have a finite proliferative capacity in vivo.

Brain hyperthermia and temperature fluctuations during sexual interaction in female rats.

Since the metabolic activity of neural cells is accompanied by heat release, brain temperature monitoring provides insight into behavior-associated changes in neural activity. In the present study, local temperatures were continuously recorded in several brain structures (nucleus accumbens, medial-preoptic hypothalamus and hippocampus) and a non-locomotor head muscle (musculus temporalis) in a receptive female rat during sexually arousing stimulation and subsequent copulatory behavior with an experienced male. Placement of the male into a neighboring compartment increased the female's temperature (approximately 0.