Brain natriuretic peptide-like immunoreactive innervation of the cerebrovascular system in the rat.

Brain natriuretic peptide is a recently discovered neuropeptide. We used an antiserum against porcine brain natriuretic peptide to identify a system of immunoreactive innervation of the cerebrovascular tree in the rat. The internal carotid artery and the proximal portions of the middle and anterior cerebral and posterior communicating arteries were the most intensely innervated by immunoreactive fibers. The density of innervation decreased distally along the anterior, middle, and posterior cerebral arteries and the basilar and vertebral arteries. Brain natriuretic peptide and the related atrial natriuretic peptide are known to cause dilatation of cerebral arteries. Our findings suggest that brain natriuretic peptide may serve as a vasodilatory neuromodulator in the cerebral circulation.