RESUMEN
BACKGROUND: Recently there have been many experiences regarding systemic effects of stellate ganglion block(SGB). During sympathetic hyperactivation, the SGB can be helpful to impaired microcirculation in brain-stem and hypothalamus. However, the exact mechanism and possible central action sites of SGB have not yet been investigated. In the present study, we traced central neural pathways following superior cervical ganglion block using the protein product(Fos) of c-fos protooncogene as a metabolic marker in a rat's brain. Method: The animals were divided into a superior cervical ganglion block group(n=5) using Marcaine 0.2 ml and a control block group(n=5) using saline 0.2ml. Medulla oblongata, pons, midbrain and hypothalamus were sectioned transversely with a sliding microtome. After imunohistochemical staining using rabbit polyclonal antibody we observed the distribution and grade of Fos expression under a light microscope. RESULTS: A blockade of superior cervical ganglion in rat led to the induction of c-fos in areas related to pain modulation sites and the autonomic nervous system; such as the parabrachial nucleus and central gray of the pons including dorsal raphe nucleus, as well as the substatia nigra of the midbrain, paraventricular hypothalamic nucleus, paraventricular thalamic nucleus posterior and habenular nucleus. CONCLUSIONS: Expressions of c-fos-like protein as a marker for neuronal activity following the blockade of the superior cervical ganglion in the rat have a part in the transcriptional control of the neurons which are related to the autonomic nervous system and endogenous pain modulation sites in the brain-stem.