Vector-Averaged Gravity Does Not Alter Receptor Single Channel Properties

Abstract

To examine the physiological sensitivity of membrane receptors to altered gravity, we examined the single channel properties of the acetylcholine receptor (AChR), in co-cultures of Xenopus myocytes and neurons, to vector-averaged gravity in the clinostat. This experimental paradigm produces an environment in which, from the cell's perspective, the gravitational vector is "nulled" by continuous averaging. In that respect, the clinostat simulates one aspect of space microgravity where the gravity force is greatly reduced. After clinorotation, the AChR channel mean open-time and conductance were statistically not different from control values but showed a rotationdependent trend that suggests a process of cellular adaptation to clinorotation. These findings therefore suggest that the AChR channel function may not be affected in the microgravity of space despite changes in the receptor's cellular organization (14).