Dopamine D1 and D2 receptor Co-activation generates a novel phospholipase C-mediated calcium signal.

Although dopamine D1 and D2 receptors belong to distinct subfamilies of dopamine receptors, several lines of evidence indicate that they are functionally linked. However, a mechanism for this linkage has not been elucidated. In this study, we demonstrate that agonist stimulation of co-expressed D1 and D2 receptors resulted in an increase of intracellular calcium levels via a signaling pathway not activated by either receptor alone or when only one of the co-expressed receptors was activated by a selective agonist.

Agonist-independent nuclear localization of the Apelin, angiotensin AT1, and bradykinin B2 receptors.

Signaling of the apelin, angiotensin, and bradykinin peptides is mediated by G protein-coupled receptors related through structure and similarities of physiological function. We report nuclear expression as a characteristic of these receptors, including a nuclear localization for the apelin receptor in brain and cerebellum-derived D283 Med cells and the AT(1) and bradykinin B(2) receptors in HEK-293T cells. Immunocytochemical analyses revealed the apelin receptor with localization in neuronal nuclei in cerebellum and hypothalamus, exhibiting expression in neuronal cytoplasm or in both nuclei and cytoplasm.

Nicotine-induced fos expression in the pedunculopontine mesencephalic tegmentum in the rat.

The aim of this study was to assess the effects of a single dose of nicotine (NIC, 0.3 or 1.0 mg/kg, s.