Effect GABA A receptors in the RVLM on cardiovascular response to the activation of the Bed nucleus of the stria terminalis in female ovariectomized rats

 

 

Effect of GABA A Receptors in the Rostral Ventrolateral Medulla on Cardiovascular

 

Response to the Activation of the Bed Nucleus of the Stria Terminalis in Female

Ovariectomized Rats
 
Masoumeh Hatam, Mahin Ganjkhani

Background:Cardiovascular diseases rarely affect women before menopause, this may suggest that estrogen might be cardioprotective.. The Bed nucleus of stria terminalis (BST) that concentrat estrogen and aromatase enzyme, this enzyme converts testosterone to estrogen.

Purpose of study:
1.Does estrogen have an affect on cardiovascular function
2.They wanted to investigate whether the inhibitory affect on cardiovascular response seen in response to stimulation of the BST was being mediated in part by the RVLM.
3. Are GABAergic mechanism involved in the RVLM to help mediate the response to stimulation of the BST.

Results:They found that glutamate into the BST caused a decrease in MAP and HR. When COCl2 was injected into the RVLM there was attentuation of the MAP and HR response. Then to determine if GABA A receptors or GABA B recptors are mediating the response bicuculline was injected into the RVLM and the BST was stimulated with glu and the response was significantly smaller than pre responses without bicuculline. They repeated the same protocol with phaclophen into the RVLM and it had no affect on the response to stimulation of the BST. The only differences they saw between the OVX +E and OVC-C was that the OVX+E had lower baseline HR.

Conclusion: These data demostrate that estrogen has an effect on cardiovascular function. It also demostrates that in response to BST stimution the activity of RVLM neurons is inhibited and this inhibition is mediated by GABA A receptors.