Effects of long-term hypoxia and hypoxic exercise on brain monoamine levels in rat

This study clarified the effects of long-term hypoxia and hypoxic exercise on monoamines in the whole brain, and in four specific regions of the rat brain. The male Wistar rat progenitors (P1 group) were randomly assigned to three groups: hypoxia (16.0% oxygen) and exercise (MHE-P1), hypoxia and sedentary (MHS-P1), normoxia and sedentary (MNS-P1). The male children of P1 (the first generation of hypoxic rats; F1) were randomly divided into two groups: hypoxia and exercise (MHE-F1) and hypoxic sedentary (MHS-F1). The monoamines of whole brain were measured in P1 males, and monoamines of cerebellum, frontal lobe, striatum and hippocampus were measured in F1 males. The monoamine levels of MHE-P1 were significantly lower than those of MHS-P1 and MNS-P1. No significant difference was found in monoamine levels between MHS-P1 and MNS-P1. Epinephrine, norepinephrine, and dopamine levels of the MHE-F1 group significantly decreased in the frontal lobe, cerebellum and striatum, compare with the other groups (hypoxic and sedentary; normoxic and sedentary, respectively). These monoamines in the hippocampus were not influenced by the hypoxia or hypoxic exercise conditions. This study suggests that long-term hypoxic exercise decreased monoamine levels in whole brain, and that sensitivity to hypoxia and hypoxic exercise differed according to brain region.