G Proteins in Rat Prefrontal Cortex (PFC) are Differentially Activated as a Function of Oxygen Status and PFC Region

摘要

This study tested the hypothesis that activation of guanine nucleotide binding (G) proteins in rat prefrontal cortex (PFC) is altered by hypoxia. G protein activation by the cholinergic agonist carbachol and the opioid agonist DAMGO was quantified using [³⁵S]GTPγS autoradiography. G proteins were expressed as nCi/g tissue in the PFC of 18 rats exposed for 14 consecutive days to sustained hypoxia (10 % O2), intermittent hypoxia (10 % and 21 % O2 alternating every 90 s), or room air (21 % O2). Relative to basal levels of G protein activation, carbachol and DAMGO increased G protein activation by approximately 70 % across all oxygen concentrations. Compared to the room air condition, sustained hypoxia caused a significant increase in G protein activation in frontal association (FrA) region of the PFC. Region-specific comparisons revealed that intermittent and sustained hypoxia caused greater DAMGO-stimulated G protein activation in the FrA than in the PrL. The data show for the first time that hypoxia increased G protein activation in PFC. The results suggest the potential for hypoxia-induced enhancements in G protein activation to alter PFC function.