The A1 Cell Group's Arterial Pressure Regulation Role as a Subset of a Multisynaptic Pathway
Yurk, Robin Ann
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Previous studies have demonstrated the importance of the central nervous system in regulation of arterial pressure through adjustments in the sympathetic nervous system and in the release of hormones such as vasopressin. Discovering a central neural circuit that integrates information from peripheral baroreceptors and produces reflex adjustment of arterial pressure is important in understanding cardiovascular control and the pathophysiological condition, hypertension. Indirect evidence has linked the role of the catecholamine cell groups, the A1(noradrenergic) and CI(adrenergic), to the tonic regulation of arterial pressure. Rats underwent stereotaxic surgery by lesioning the Al and CI cell groups with the neurotoxins 6-hydroxydopamine and kainic acid. Arterial pressure was monitored pre- and post- lesion to determine the effects of the neurotoxins on the cell groups. The rat brains were removed and processed using thionin staining and immunohistochemical techniques in-order to verify the location of the lesions. 6-Hydroxydopamine was found not to be an effective noradrenergic neuronal neurotoxin, and kainic acid was nonspecific in its destruction destroying noradrenergic and noradrenergic cell groups in the area). In conclusion, a specific neuronal neurotoxin for the Al norepinephrine cell groups is necessary for directly testing the role of the medullary cell group network and its relationship to the baroreflex circuit.