Igmesine is a sigma-1 receptor agonist. It was assayed in clinical trials targeting major depressive disorder. Igmesine is the only antisecretory agent that we have tested to date that inhibits both cholera toxin and the E. coli enterotoxins. Sigma receptors are known to be present on nerves in the enteric nervous system and this would seem to be a potentially useful class of drugs to pursue for the treatment of secretory diarrhoea in humans. It was shown that when Alzheimer's disease rats were submitted to the conditioned fear stress test, igmesine can significantly reduce the stress-induced motor suppression, indicating exogenous σ-1 receptor agonists may alleviate Alzheimer's disease-associated depressive symptoms.