GR-113808 is a drug which acts as a potent and selective 5-HT₄ serotonin

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

antagonist. It is used in researching the roles of 5-HT₄ receptors in various processes, and has been used to test some of the proposed therapeutic effects of selective 5-HT₄ agonists, such as for instance blocking the

nootropic Nootropics ( , or ) (colloquial: smart drugs and cognitive enhancers, similar to adaptogens) are a wide range of natural or synthetic dietary supplement, supplements or drugs and other substances that are claimed to improve cognitive function ...

effects of 5-HT₄ agonists, and worsening the respiratory depression produced by

opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

analgesic drugs, which appears to be partly 5-HT₄ mediated and can be counteracted by certain 5-HT₄ agonists.

References

5-HT4 antagonists Tertiary amines Piperidines Indoles Carboxylic acids Sulfonamides {{nervous-system-drug-stub