Negative aging stereotypes and the agentic-communal dichotomy.

Prior research has documented negative aging stereotypes. Our hypothesis is that these only apply when a certain dimension of traits is employed and when older persons occupy certain roles. 42 college students were asked to rate the extent to which each of several "agentic" traits, e.g., active, aggressive, independent, and "communal" traits, e.g., understanding, warm, helpful, characterized a roommate and college professor, both of whom were stated to be either 23 or 65 years of age. For the roommate (but not the professor), the young person was seen as more agentic than the older person. No differences were found on the dimension of communality. It was concluded that young college students may attribute negative behaviors to older persons but this is more likely when the negative behaviors are agentic in nature and the older person occupies certain roles such as "retired person."

Gene-based neurotransmitter modulation in cerebellar granule neurons.

The human glutamic acid decarboxylase (GAD) gene was transferred into rat cerebellar granule neurons. Following adenoviral-mediated gene transfer, nearly 100% of the neurons had transgene expression that persisted for the duration of their survival in culture. GABA levels were elevated both in the growth media and in lysates of GAD-modified granule neurons. In GAD-modified neurons, extracellular GABA levels steadily increased with time, whereas intracellular GABA levels peaked 10 days after gene transfer. GAD-modified neurons released both glutamate and GABA into the surrounding media before and after potassium-induced stimulation, but only the release of glutamate was sensitive to potassium stimulation. These data suggest that glutamatergic neurons, which initially contained no detectable GABA, can be genetically modified to release GABA constitutively.