Neurogenic mediation of serum-induced microvascular constriction.

We have used the rat hippocampal slice preparation as a model system for the study of microvascular vasospasm. Penetrating cerebral microvessels in the slice constrict in response to a variety of stimuli, including serum from coagulated blood. Microvascular responses to many stimuli are associated with changes in the activity of nearby neurons, and in some cases can be shown to be neurogenically mediated. Here we use the selective neurotoxin, tetrodotoxin (TTX), to show that serum-induced constriction is also neurogenically mediated. This neural regulation of microvessel caliber may participate in pathological vasoconstriction mechanisms in the whole animal.