Loss of Contact in Space Alters Dopamine System in <i>C. elegans</i>

Abstract

Progressive neuromuscular decline is a prominent health concern preventing the world’s ambition of interplanetary human habitation. The precise causes of this decline and effective countermeasures remain elusive. We establish faltering dopamine signalling as a consistent feature across multiple spaceflight exposures and during simulated microgravity in C. elegans , which can be prevented with dopaminetargeting treatments. Loss of mechanical contact stimuli in microgravity induces dopamine-mediated functional impairments. Reinstating physical contact events also improves dopamine signalling, neuromuscular performance and associated calcium handling. This study reveals that reduced contact stimuli in microgravity causes dopamine-induced neuromuscular failure and that targeting this system through the external environment (contact stimuli), or clinically available drugs (dopamine pathway) are realistic, viable treatment strategies to promote safe human deep space travel.