Substantia nigra stimulation and blood pressure effects of locally applied kainic acid

Abstract

Cardiovascular response to electrical stimulation of the substantia nigra were studied in awake, unrestrained cats. Significant increases in the arterial blood pressure, heart rate and respiratory rate appeared simultaneously with the somatomotor effects of stimulation. Twenty-four hours after local microinjection of kainic acid into the site of stimulation the blood pressure responses to stimulation were reduced by 70%, while the changes in heart rate and respiratory rate effects were not statistically significant. Intense somatomotor effects appeared about 30 min after the injection. However, the animal recovered much of its behavioural functions within five hours. It is concluded that the substantia nigra, besides its somatomotor functions, has a role in regulation of blood pressure.