Abstract
Summary
The arterial blood pressure responses in rats after intravascular levodopa administration were measured for the first time with direct methods in unanesthetized, unrestrained animals after full recovery from surgical stress due to the cannulation. The observed results were compared with results collected from anesthetized animals (nembutal or halothane). After levodopa administration, the mean arterial blood pressure of all rats was increased, reaching the peak value 2-5 min later. The animals in halothane anesthesia had a small rise of the mean arterial blood pressure. Doubling the dose of levodopa increased further the hypertensive responses in unanesthetized animals but not in nembutal anesthesia. Percentage-wise, levodopa caused a much greater increase of the mean arterial blood pressure in nembutal groups than in unanesthetized animals. However, the peak values were the same, around 170-180 mmHg, in all nembutal anesthetized animals as in unanesthetized animals that received a double dose of levodopa (20 mg/kg).
This research was supported by the Office of Naval Research Contract No. N00014-76-C-0926 with funds provided by the Naval Medical Research and Development Command.
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