The Vasoactivity of Norepinephrine in the Bed Nucleus of the Stria Terminalis (2013)
Undergraduates: Laura Kim, Elizabeth Bucher
Faculty Advisor: R. Mark Wightman
Department: Biology
A network of intraparenchymal microvessels in the brain delivers oxygen and other nutrients to meet the metabolic demands of the brain. There is evidence that neurotransmission in the microenvironments of the brain control blood flow and the delivery of these nutrients. The aim of this study was to investigate the vasoactivity of α1, α2, and β adrenergic receptors in the ventral bed nucleus of the stria terminalis (vBNST). Fast scan cyclic voltammetry (FSCV) was used to make measurements in vivo following electrical stimulation of the ventral noradrenergic bundle. A tri-phasic oxygen response was measured with norepinephrine release. To assess whether oxygen changes in this region are regulated by noradrenergic signaling, antagonistic drugs selective for each receptor type were administered intraperitoneally. Terazosin, an α1 antagonist, reduced the first peak to 10¿4% of its original amplitude. Administration of idazoxan, an α2 antagonist, completely eliminated the second peak, while desipramine , a norepinephrine transporter blocker, had the opposite effect, increasing the oxygen decrease to 179¿19% of the control value. Lastly, propranolol, a β antagonist, eliminated the third oxygen peak. These pharmacological results suggest that norepinephrine can indeed influence cerebral blood flow dynamics.