Development of an Efficacious Exercise as a Counter Measure of Muscle Atrophy

摘要

The following study was done in males earlier and was essentially repeated in females. Normal rats were anesthetized and prepared for one of the following procedures using the tibial (T), peroneal (P), sural (Su), and/or soleus (So) nerves: sham control - dissection of the nerves but no transection or stimulation; nerve transection and stimulation of the proximal end of T, P and Su; nerve transection and stimulation of the distal end of T, P and Su; nerve transection and stimulation of proximal end of T and Su. Maximum stimulation (at a rate and duration mimicking that observed during treadmill stepping) was administered to the nerves via bipolar silver electrodes using a Grass stimulator for 15 min. At the conclusion of the stimulation, a blood sample was taken by cardiac puncture and the rats were sacrificed immediately. The anterior pituitary gland and hypothalamus were removed as rapidly as possible. Pituitary and plasma bio-active and immuno-active GH were measured. Plasma T3, T4, corticosterone, testosterone, glucose, triglycerides and lactate levels were also determined. Stimulation of the proximal end of either the T, P and Su or T and Su resulted in a significant decrease in the pituitary and increase in the plasma bioactive GH levels. No change in any other parameter was observed. In contrast, no changes were observed when the distal end of the cut nerves were stimulated. These data clearly demonstrate that sensory input from the periphery is an important source of control of GH secretion. These data are in agreement with the observation that GH secretion is inhibited during both spaceflight and hindlimb suspension and elevated during exercise. These data showed that the response was similar in male and female rats.