Abstract

The unanesthetized monkey and rabbit exhibit a well-defined and sustained decline in systolic and diastolic blood pressure following intravenous administration of the ganglionic blocking agent chiorisondamine chloride.

In contrast, the unanesthetized normotensive dog and rat do not respond with a persistent fall in blood pressure following administration of ganglionic blocking agents. The diastolic blood pressure response of the unanesthetized chronic renal hypertensive dog and neurogenic hypertensive dog is likewise not prolonged.

In the malignant phase of renal hypertension the dog responds with a sustained systolic and diastolic decline following chlorisondamine chloride injection.

Normotenaive dogs and rats under anesthetic doses of pentobarbital or Dial-Urethane respond with well-defined and sustained falls in both systolic and diastolic pressures following intravenous injection of ganglionic blocking agents. In contrast to unanesthetized dogs, dogs under barbiturate anesthesia exhibit a relative bradycardia following administration of ganglionic blocking agents.

Evidence has been presented which indicates that the barbiturates interfere with compensatory mechanisms which normally function in the normotensive dog and rat during "ganglionic blockade." These compensatory mechanisms appear to be generally less predominant in the monkey and rabbit.