 In addition to its actions on GABA receptors, allopregnanolone, like progesterone, is known to be a negative allosteric modulator of nACh receptors, and also appears to act as a negative allosteric modulator of the 5-HT3 receptor.Along with the other inhibitory neurosteroids, allopregnanolone appears to have little or no action at other ligand-gated ion channels, including the NMDA, AMPA, kainate, and glycine receptors.Unlike progesterone, allopregnanolone is inactive at the classical nuclear progesterone receptor (PR).