Ae. Elhusseini et al., NITRIC-OXIDE REGULATES CYCLIC GMP-DEPENDENT PROTEIN-KINASE PHOSPHORYLATION IN RAT-BRAIN, Journal of neurochemistry, 71(2), 1998, pp. 676-683
Nitric oxide (NO) acts via soluble guanylyl cyclase to increase cyclic
GMP (cGMP), which can regulate various targets including protein kina
ses. Western blotting showed that type II cGMP-dependent protein kinas
e (cGK II) is widely expressed in various brain regions, especially in
the thalamus. In thalamic extracts, the phosphorylation of several pr
oteins, including cGK ii, was increased by exogenous NO or cGMP. In vi
vo pretreatment with a NO synthase inhibitor reduced the phosphorylati
on of cGK II, and this could be reversed by exogenous NO or cGMP. Conv
ersely, brainstem electrical stimulation, which enhances thalamic NO r
elease, caused a NO synthase-dependent increase in the phosphorylation
of thalamic cGK II. These results indicate that endogenous NO regulat
es cGMP-dependent protein phosphorylation in the thalamus. The activat
ion of cGKII by NO may play a role in thalamic mechanisms underlying a
rousal.