Histochemical and immunohistochemical study of noradrenergic, serotonergic and peptidergic innervation of the cerebral circulation.

Using fluorescence histochemistry, we have examined the origin of noradrenaline (NA)-, 5-hydroxytryptamine (5-HT)- and neuropeptide Y (NPY)-containing perivascular nerve fibres supplying the major cerebral arteries of the gerbil, and the effect of superior cervical ganglionectomy on their cerebrovascular density and distribution. Bilateral ganglionectomy resulted in a complete loss of these perivascular nerve types in the anterior circulation, while a few fibres still persisted in the posterior circulatory bed. In addition, we demonstrate the presence of both 5-HT- and NPY-positive cell bodies in the superior cervical ganglion (SCG) of adult gerbils, suggesting that the main origin of cerebrovascular 5-HT- and NPY- (as well as NA-) containing nerve fibres is in the SCG.