Role of calcium/calmodulin-dependent protein kinases in expression of Fos protein in the nucleus tractus solitarii after sustained hypertension

Nitric Oxide Regulates c-fosExpression in Nucleus Tractus Solitarii Induced by Baroreceptor Activation via cGMP-Dependent Protein Kinase and cAMP Response Element-Binding Protein Phosphorylation

“…The arterial baroreceptors were activated by a sustained increase in MSAP evoked by i.v. infusion of phenylephrine (10 g/kg/h) (Sigma-Aldrich, St. Louis, MO) for 30 min (Chan et al, 1998b(Chan et al, , 1999(Chan et al, , 2000. The infusion rate was adjusted (5-7 l/kg/h) to maintain an average elevation in MSAP of 45 to 50 mm Hg.…”

“…Activation of the arterial baroreceptors induces Fos expression (Chan and Sawchenko, 1998;Chan et al, 1998bChan et al, , 1999Chan et al, , 2000 in the barosensitive neurons of nucleus tractus solitarii (NTS), the principal terminal site of primary baroreceptor afferents (Ciriello, 1983). This induced Fos expression represents an early intracellular event that leads to long-term inhibitory modulation of the baroreceptor reflex (BRR) response (Shih et al, 1996;Chan et al, 1997).…”

“…Activation of the glutamate receptors at the NTS by baroreceptor afferents results in activation of calcium/calmodulin-dependent protein kinases (CaM kinases), leading to phosphorylation of CREB and activation of CRE in the promotor of the c-fos gene (Chan et al, 1999(Chan et al, , 2000. Calcium/ calmodulin also activates the neuronal nitric-oxide synthase (nNOS) (Bredt and Snyder, 1990).…”

Inhibition of Baroreflex by Angiotensin II via Fos Expression in Nucleus Tractus Solitarii of the Rat

“…It is generally contended 24,25 that AT 1 R are coupled via G protein or proteins to stimulation of inositol phospholipid hydrolysis, followed by an increase in calcium mobilization or protein kinase C. Speculatively, the same signal transduction pathways may also underlie the inhibitory action of Ang II via AT 1 R at the NTS. Workers at our laboratory demonstrated recently that induction of the c-fos gene in the NTS after baroreceptor stimulation involves activation of calcium/calmodulin kinases 8 and phosphorylation of the transcription factor cAMP response element binding protein. 7 Other authors 13 pointed out that transcriptional regulation of c-fos by Ang II is achieved via the protein kinase C pathway and involves the serum response element, the binding site for the dimeric serum response factor.…”

“…s the principal terminal site of the primary baroreceptor afferents, 1 the caudal nucleus tractus solitarii (NTS) in the medulla oblongata has become a major focus in recent studies [2][3][4][5][6][7][8][9] on the anatomic and temporal specificity of Fos expression after cardiovascular perturbations. In terms of function, workers at our laboratory reported that both basal 6 and induced 4 Fos expression in the caudal NTS may represent an early step in the cascade of intracellular events that leads to long-term inhibitory modulation of baroreceptor reflex (BRR) response.…”