Yasunori Umemoto Vineet C Chitravanshi


Traumatic brain injury (TBI) leads to cardiovascular complications and negative impact on the recovery of these patients. There are not much published reports regarding the alterations in brain areas controlling cardiovascular function in TBI. In this study, we investigated the effects of severe, moderate and mild TBI on systemic blood pressure, heart rate, greater splanchnic nerve activity (GSNA) and baroreflex. The experiments were done in anesthetized, male Wistar rats. Fluid percussion injury (FPI) was applied to induce TBI. Application of severe, moderate and mild FPI resulted in 100%, 40% and 10% mortality, respectively. In moderate and mild FPI, apnea was observed for 38.2 ± 17.3 and 14.8 ± 3.6 sec, respectively, however, no apnea was seen in severe FPI treated rats, since most of the rats in this group died just after the injury. The decreases in MAP and HR at 30 minutes, 1, 2, 4 and 6 hours after the moderate and mild FPI were significantly attenuated when compared with sham control rats. The GSNA and baroreflex sensitivity were significantly attenuated after moderate and mild FPI. In these rats, microinjections of L-glutamate and gabazine into medullary areas elicited altered cardiovascular responses. These results indicate that both moderate and mild FPI elicit cardiovascular changes.