PT  - JOURNAL ARTICLE
AU  - M. Luisa Capece
AU  - Helen A. Baghdoyan
AU  - Ralph Lydic
TI  - Carbachol Stimulates [<sup>35</sup>S]Guanylyl 5′-(γ-Thio)-Triphosphate Binding in Rapid Eye Movement Sleep-Related Brainstem  Nuclei of Rat
AID  - 10.1523/JNEUROSCI.18-10-03779.1998
DP  - 1998 May 15
TA  - The Journal of Neuroscience
PG  - 3779--3785
VI  - 18
IP  - 10
4099  - http://www.jneurosci.org/content/18/10/3779.short
4100  - http://www.jneurosci.org/content/18/10/3779.full
SO  - J. Neurosci.1998 May 15; 18
AB  - Carbachol enhances rapid eye movement (REM) sleep when microinjected into the pontine reticular formation of the cat and rat. Carbachol elicits this REM sleep-like state via activation of postsynaptic muscarinic cholinergic receptors (mAChRs). The present study used in vitro autoradiography of carbachol-stimulated [35S]guanylyl-5′-O-(γ-thio)-triphosphate ([35S]GTPγS) binding to test the hypothesis that carbachol activates mAChRs to induce stimulation of G-proteins in brainstem nuclei contributing to REM sleep generation. The results demonstrate a heterogeneous increase in carbachol-stimulated G-protein activation across rat brainstem. Binding of [35S]GTPγS in the presence of carbachol, compared with basal binding, was significantly increased in the laterodorsal tegmental nucleus (75.7%), caudal pontine reticular nucleus (68.9%), oral pontine reticular nucleus (64.5%), pedunculopontine tegmental nucleus (55.7%), and dorsal raphe nucleus (54.0%) but not in the nucleus locus coeruleus. The activation of G-proteins by carbachol was concentration-dependent and antagonized by atropine, demonstrating that G-proteins were activated via mAChR stimulation. The results provide the first direct measures of mAChR-activated G-proteins in brainstem nuclei known to contribute to REM sleep generation.