Effects of selective Bcl-2 inhibitor HA14-1 treatments on functional activity of magnocellular vasopressinergic neurons of rat hypothalamus

Immunohistochemical expression of Bcl-2, p53 and caspase-9 in hypothalamus magnocellular centers of nNOS knockout mice following water deprivation

We studied the interactions between apoptosis regulator proteins (Bcl-2, p53 and caspase-9) and neuronal nitric oxide in vasopressinergic magnocellular centers of the hypothalamus using neuronal nitric oxide synthase (nNOS) gene knockout mice. nNOS gene deletion resulted in accumulation of Bcl-2, p53 and caspase-9 in the paraventricular (PVN) and supraoptic (SON) nuclei in controls. Dehydration increased the levels of all three apoptosis regulator proteins studied in nuclei of wild type mice. In the hypothalamus magnocellular centers of nNOS knockout mice, however, expression of Bcl-2, p53 and caspase-9 was unchanged after dehydration. The number of magnocellular neurons did not change in the SON and PVN of nNOS deficient mice compared to wild type, and after dehydration, cell death was not observed in either nucleus of wild type or knockout mice despite activation of apoptosis regulator protein expression. Thus, we demonstrated that gene disruption of nNOS prevents activation of Bcl-2, p53 and caspase-9 expression during water deprivation, and that nNOS deficiency did not affect survival of magnocellular neurons of the hypothalamus.

Repeated cocaine administration increases B-cell leukemia/lymphoma 2 phosphorylation in the rat dorsal striatum

Protein phosphorylation caused by drug administration is a critical step in the regulation of behavioral alterations. This study was conducted to determine how repeated exposure to cocaine phosphorylates B-cell leukemia/lymphoma 2 (Bcl2), which may be responsible for the regulation of behavioral alterations in the rat dorsal striatum. The results revealed that repeated systemic injections of cocaine (20 mg/kg) once a day for 7 consecutive days increased the phosphorylation of Bcl2 at serine 70 (Bcl2-S70). However, this increase was reduced by the blockade of dopamine D1 receptors, group I metabotropic glutamate receptors (mGluRs), and N-methyl-D-aspartate (NMDA) receptors. In addition, elevation of behavioral locomotor activity after repeated exposure to cocaine was partially reduced by the inhibition of Bcl2. These data suggest that stimulation of dopamine D1 receptors, group I mGluRs, and NMDA receptors following repeated cocaine administration is necessary for the induction of Bcl2-S70 phosphorylation, which contributes to the expression of behavioral sensitization.