It has been proposed that both gap junction coupling and GABAergic mechanisms contribute to the regulation of respiratory rhythm generation. Furthermore, studies suggest that electrical synapses containing the gap junction protein connexin36 (Cx36) are critical for the generation of widespread synchronous activity among inhibitory interneurons in some CNS regions (e.g., cortex, hippocampus). Although the gap junction protein Cx36 has been identified in respiratory-related brainstem regions, it is unclear whether GABAergic neurons express Cx36 in these regions. Therefore, double label immunohistochemical protocols were employed on medullary tissue sections obtained from adult rats (81-125g, ~5-6 wk old) to determine whether GABAergic neurons express the gap junction protein Cx36. To localize GABAergic neurons, a primary antibody directed against parvalbumin was used. To identify Cx36, a primary antibody directed against a sequence in the cytosolic loop between the second and third transmembrane domains of rat and mouse Cx36 was used. The results of these experiments will relate gap junction proteins (specifically Cx36) to the GABAergic inhibitory network in the central respiratory system, and will further extend the results of previous studies to brainstem mechanisms for neuronal communication.

This work was supported by the Simons Foundation and NIH Grant HL63175.