#ozr

Domitila  A. Huber and Ann M. Schreihofer

Obese Zucker  rats (OZR) have elevated sympathetic nerve activity (SNA) and mean arterial pressure  (MAP) compared with lean Zucker rats (LZR). The aim of the present study was  to determine whether elevated SNA and MAP in OZR was due to altered tonic  glutamatergic, angiotensinergic, or GABAergic inputs to the rostral  ventrolateral medulla (RVLM).

     Inhibition of the RVLM produced  comparable reductions in SNA and HR in LZR and OZR but evoked a greater  decrease in MAP in OZR compared with LZR. The SNA and MAP were not further  reduced by subsequent injection of the ganglionic antagonist mecamylamine.

      In OZR, bilateral microinjection of AT1  receptor antagonist losartan in the RVLM produced modest decreases in SNA,  HR, and MAP but in LZR, the changes in HR were comparable to OZR, but the  effects of losartan on SNA and MAP were negligible.

      Stimulation of the sciatic nerve before  the microinjections reliably produced increases in SNA, HR, and MAP and these  responses were eliminated or reversed after bilateral microinjection of glutamate  receptor antagonist kynurenate into the RVLM.

      Inhibition of GABAA receptors  by bilateral microinjection of gabazine in the RVLM evoked significantly smaller  increases in SNA, HR, and MAP in OZR compared with LZR and subsequent microinjection  of kynurenate in the RVLM evoked comparable decrease in SNA, HR and MAP.

      Antagonism of GABAA receptors  in the RVLM and subsequent antagonism of ionotropic glutamate receptors in  the caudal ventrolateral medulla (CVLM) evoked attenuated increases in SNA and  HR in OZR compared with LZR.

     After microinjections of kynurenate  into the CVLM, microinjections of GABA into the RVLM produced decreases in  SNA, HR, and MAP that were not different between OZR and LZR. Inhibition of  the NTS evoked increases in SNA, HR, and MAP and abolished phenylephrine-  induced reductions in SNA and HR and phenyl biguanide- induced reductions in  SNA, HR, and MAP.

     These results suggest the elevated SNA  and MAP in OZR is derived from the RVLM and that enhanced angiotensinergic  activation and reduced GABAergic inhibition of the RVLM may contribute to the  elevated SNA and MAP in the OZR.

Mahesh kumar Sivasubramanian

Kynes - I'm Back.

Summer is still here, so Kynes provides a soothing new track perfect for the sunny season entitled "I'm Back." Lots of cool stuff here including some vibrant vocal samples, impressive transitional work, and a lighthearted atmosphere. Check out this track and more on OZR's latest mixtape, Bummer 13.