The neurosteroids that target the a4 and a6 GABAa are interesting but usually just used as anaesthetics in the past I thought, they had different toxicity problems so they were reserved for veterinary use so maybe that's why they didn't see much recreational use, not that that stopped ketamine lol. There is a weird dose response to some of those neurosteroids too but I imagine if you got the dose right (not too low or high) they could be recreational if you don't just get sedated. http://www.cell.com/neuron/abstract/S0896-6273(11)01093-2
I guess alcohol has activity at those strange extrasynaptic GABAa receptors too, wonder how much it plays into its effects. the paper above said its a key target of alcohol anywho. I'd love to hear a trip report on galaxolone though...