Reversal of cerebral vasospasm by sphenopalatine ganglion stimulation in a dog model of subarachnoid hemorrhage.

Background: Sphenopalatine ganglion stimulation dilates the ipsilateral arteries of the normal dog anterior circle of Willis. This experiment tested whether similar stimulation would reverse cerebral vasospasm.

Methods: Six dogs underwent baseline angiography followed by creation of subarachnoid hemorrhage (SAH) by injection of autologous blood into the cisterna magna.

Blood-brain barrier opened by stimulation of the parasympathetic sphenopalatine ganglion: a new method for macromolecule delivery to the brain.

Object: Drug delivery across the blood-brain barrier remains a significant challenge. Based on earlier findings, the authors hypothesized that parasympathetic innervation of the brain vasculature could be used to augment drug delivery to the brain.

Methods: Using a craniotomy-cerebrospinal fluid superfusate paradigm in rats with an intravenous injection of tracer the authors demonstrated that stimulation of the postganglionic parasympathetic fibers of the sphenopalatine ganglion (SPG) increased the concentration of fluorescein isothiocyanate-dextran (4-250 kD) in the superfusate by two- to sixfold.

Increased BBB permeability by parasympathetic sphenopalatine ganglion stimulation in dogs.

The blood-brain barrier (BBB) is a major obstacle for movement of large molecules to and from the brain. Stimulation of the sphenopalatine ganglion (SPG), the major source of parasympathetic innervation to brain vasculature, is known to vasodilate brain vessels, and has recently been shown to also increase the permeability of the BBB in the rat. In this work, we studied the effect of SPG stimulation on BBB permeability in larger animals--Beagle dogs.