The angiotensin AT₂ receptor modulates T‐type calcium current in non‐differentiated NG108‐15 cells

Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels

“…ANG II and the AT 2 selective ligand CGP-42112 inhibited by 25% the T-type current in NG108 -15 cells (58,59). Inhibition was associated with a Ϫ5-mV shift in the I-V but no effect on the h ϱ curve.…”

The angiotensin type 2 receptor of angiotensin II and neuronal differentiation: from observations to mechanisms

“…In the adult rat, the AT 2 receptor was found at high levels in the medulla oblongata (control of autonomous functions), in septum and amygdala (associated with anxiety-like behavior), in the thalamus (sensory perception), in the superior colliculus (control of eye movements in response to visual information) as well as in the subthalamic nucleus and in the cerebellum (areas associated with learning of motor functions) (Song et al 1992, Lenkei et al 1996. According to Bottari et al (1992) and our observations in rat cerebellar granule cells in culture (Fig. 1A), AT 2 receptors are found on neurons, but not on astrocytes or glial cells.…”

“…In cells of neuronal origin, activation of the AT 2 receptor was shown to promote changes in the expression of different ion channels leading to modifications in neuronal excitability. In NG108-15 cells, Buisson et al (1992Buisson et al ( , 1995 showed that Ang II induced an inhibition of current amplitude attributed to T-type calcium channels by a mechanism involving activation of an unidentified phosphotyrosine phosphatase and a pertussis toxin (PTX)-insensitive G-protein. On the other hand, in rat brain neuronal cultures Kang et al (1993) showed that activation of the AT 2 receptor stimulated a delayed-rectifier K + current (I K ) and a transient K + current (I A ) through both a PTX-sensitive G-protein (G i ) and PP2A, a serine/ threonine phosphatase (Kang et al 1994).…”

Angiotensin II receptor pharmacology and AT1-receptor blockers

“…The phospholipase C activation results in the generation of 1, 4, 5-trisphosphate and diacylglycerol, leading to an activation of protein kinase C and an increase in intracellular calcium levels via L-type calcium channels. [52][53][54] The rise in intracellular calcium is associated with typical AT 1 -receptor-associated responses such as vasoconstriction and secretion of aldosterone. The cascade induced by phospholipase D and A 2 leads to the formation of fatty acids.…”

“…In their studies, stimulation of the cloned AT 2 receptor, transiently expressed in COS-7 cells, failed to increase IP 3 or intracellular calcium, and no apparent effects on cAMP and cGMP levels and phosphotyrosine phosphatase activity could be observed. In NG 108-15 cells, which constitutively express AT 2 receptors, Buisson et al 54 found that AT 2 receptor stimulation results in the inhibition of T-type calcium channels through an as yet undefined pathway. [52][53][54] In another cell line from rat pheochromocytoma, PC12W, which only expresses AT 2 receptors, Bottari and colleagues 60,78 reported that Ang II stimulates a membrane-associated phosphotyrosine phosphatase and inhibits ANP-sensitive particulate guanylate cyclase via a G-protein-independent pathway.…”