Plasma catecholamine levels during cold adaptation and hibernation in woodchucks ( Marmota monax)

Abstract

1. 1.|Plasma catecholamines (dopamine, norepinephrine and epinephrine) were measured in non-hibernating (summer) and hibernating woodchunks ( Marmota monax). Summer animals were warm (24°C) or cold (9°C) adapted for 3 weeks before blood samples were collected. 2. 2.|In summer, norephinephrine (NE) concentration after cold acclimation was double the level found at warm ambient temperature. Epinephrine (E) and dopamine (DA) concentrations were not significantly different between warm and cold acclimation. 3. 3.|During entrance into and in deep hibernation, all catecholamine values were significantly lower than cold-adapted levels. With arousal from hibernation, all catecholamines rose markedly above the summer values. The variation in plasma catecholamine levels reflect dramatic changes in the adrenosympathetic axis during all stages of hibernation.