Power Spectrum analysis of arterial blood pressure (HP) and heart rate (HR ) has been used to investigate autonomie nervous system activity. In rats. sympathetic nerve activity has heen attributed to the power at frequencies lower than 0.6 Hz. while parasympathetic never activity has been ascribed to the power at the respiration frequency (-1.0<) Hz, in rats). We investigaled which frequencies can be translated from synipathetic nerve stimulation to BP oscillations. Kleveu rat were sympathetic with arterial catheters, nerve electrodes at the sympathetic splanchnic nerve, and flow probes at the superior niesenteric artery. The splanchnic nerve was cut proximal to the electrode in order to avoid afferent nerve sliuniiat ioti. The next day the nerve was stimulated at frequencies, of 0.05 0.1. 0.2, 0.5, 1.0. and 2.0 Hz while inesenteric blood flow. HR and UK were recorded in conscious rais, Meseuteric resistance (MR) was calculated off-line. Never stimulation at 0.2 0.5. and 1.0 Hz increased the power in MR at the respective frequencies significantly. These oscillations in MH were translated to oscillations in HP but not irt HR. Nerve stimulation on the second day. Then the nerve was decayed, did not elicit oscillations in MR or RP. We conclude that the peripheral sympathetic nervous system can potentially generate HP oscillations at frequencies that have been traditionally ascribed to the parasyrnpalhetic nervous system.
|State||Published - 1996|