NMDA and GABA receptor presence in rat heart mitochondria

The purpose of this study is to demonstrate the presence of three more receptors in mitochondria. Two N-methyl-d-aspartate receptor (NMDAR) subunits (NR1 and NR2B) are found by protein immunoblot and immunogold labeling in mitochondria fraction isolated from rat heart. These data allow supposing NMDAR presence and functioning in the inner mitochondrial membrane. There are no signs of receptor presence obtained in heart tissue lysate, that indicates the receptor localization exactly in mitochondria. The possible receptor functions discussed are its participation in calcium transport and in excitation-metabolism coupling. Besides, preliminary evidence is obtained of GABAA and GABAB receptors presence in heart mitochondria. One can surmise their role in metabolism regulation and their possible co-operation with NMDAR just as in the nervous system.