Functional cardiovascular action of L-cysteine microinjected into pressor sites of the rostral ventrolateral medulla of the rat

Yumi Takemoto Amino Acids (2014) 46:863–872 DOI 10.1007/s00726-013-1651-5 The main purpose of this study was to determine the cardiovascular response to L-cysteine microinjection into the RVLM. They also investigated cardiovascular responses to D- cysteine and N-acetyl-L-cysteine. They used Wistar rats and did microinjections using L-cysteine, D-cysteine, L-glumate, MK801 antagonist against NMDA iEAA receptors and CNQX is an antagonist against non NMDA. They injected L- cysteine caused and increase blood pressure. Injections of L-cysteine and L-glutamate caused a dose dependent increase in blood pressure and in HR. In response to D- cysteine and N-acetyl-cysteine there were no changes in BP and HR. When the CNQX and MK801 were given prior to the injection of L-cysteine, BP and HR responses were attenuated. These data suggest that t L-cysteine does have the ability to increase neuronal activity, and could be a possible neurotransmitter. This study also demonstrated that when MK801 was given alone and then L-cysteine was injected BP and HR responses were attenuated. The results from this study suggest that the response to L-cysteine was due to activation of iEAA receptors in the RVLM. –MD