Role of ventrolateral medulla in vasomotor response to cerebral ischemia

Dampney and Moon Am J Physiol. 1980 Sep;239(3):H349-58. In this article they wanted to investigate whether the ventrolateral medulla was responsible for the pressor response that occurs in response to cerebral ischemia in anesthetized paralyzed rabbits. They lesioned the ventrolateral medullar reticular formation, this produced depressor responses. They gave 40ug/ml norepinephrine in order to bring blood pressure near baseline blood pressure values before lesion. Then cerebral ischemia was induced and this caused no change in the animals that received electrical destruction of the ventrolateral medullar reticular formation when compared to the control pressor responses to CIR. When the dorsal medulla was electrically destroyed the pressor responses still persisted in response to CIR. They also lesioned the ventrolateral medulla area more laterally and they found that this did not alter the pressor response that occurred in response to the CIR. They also did some mapping of the ventrolateral medulla using electrophysiology because this area had not been characterized before this. Overall they showed that the ventrolateral medulla is playing an important role in mediating the CIR response. -MD