Oxytocin/Osteocalcin/IL-6 and NGF/BDNF mRNA Levels in Response to Cold Stress Challenge in Mice: Possible Oxytonic Brain-Bone-Muscle-Interaction.

Oxytocin (Oxt), osteocalcin (Ost), and NGF/BDNF have a role in bone homeostasis, reproduction, and cognition. Oxt/Ost is required for muscle repair. We investigated gene response of muscle and the inter-organ communication following cold stress (CS). The mRNA quantity of , , , , , , , , , , and genes in bone, brain, soleus (SOL), and (TA) muscles from adult mice following CS were investigated. The myosin heavy-chain , , , and gene expression were investigated. Mice were maintained at = 23°C or 4°C for 6 h and 5-days (5d). CS mice did not show signs of muscle degeneration. An upregulation of and genes by 2 and 1.5 folds, respectively, in TA after 6 h CS and by 4 and 22 folds in SOL muscle after 6 h and 5d CS, respectively, was observed; while after 6 h CS was downregulated in either muscle. was unaffected, while after 5d CS was upregulated in TA. was downregulated in SOL by 0.9-folds at 5d. Following 5d CS, and genes were upregulated, respectively, by 1 and 1.5 folds in SOL. A downregulation of , respectively, by 0.96 and 0.88-folds after 6 h and 5d CS in SOL and was also downregulated by 0.88-fold after 5d CS in TA. and were not affected. Changes in the expression levels of genes in TA and SOL muscles, bone, and brain following CS were regulated by IL6 and Oxt. CS potentiates the slow-twitch phenotype of SOL which is in line with the metabolic need of this muscle, and the potentiation of the slow-twitch phenotype in TA. Oxt and IL6 coordinate a phenotype-dependent tonic effect of slow-twitch muscle and Oxt regulates the inter-organ interaction between brain and SOL muscle. Muscle tropism is maintained by NGF signaling following CS.