Disclosed herein are bicyclic heterocyclic spiro compounds of formula I, wherein the substituents are as defined in the specification, compositions comprising said compounds, processes for their preparation and uses thereof. Said compounds are useful ligands for G-protein coupled receptors (GPCRs) and are particularly useful as muscarinic receptor agonists as such are useful in the treatment of conditions such as insulin resistance syndrome, type 2 diabetes, Alzheimers disease. Examples of particularly preferred compounds include: (1-(2,8-dimethyl-1-thia-3,8-diazaspiro[4.5]dec-3-yl)-3-(1H-indol-3-yl)propan-1-one) 1-(2,8-Dimethyl-1-thia-3,8-diazaspiro[4.5]dec-3-yl)-3-(1-methyl-indol-3-yl)propan-1-one (3-(4-fluorobenzenesulfonyl)-2,8-dimethyl-1-thia-3,8-diazaspiro[4.5]-decane) 1-(2,8-dimethyl-1-oxa-3,8-diazaspiro[4.5]dec-3-yl)-3-(1H-indol-3-yl)-propan-1-one (1-(2,8-dimethyl-1-oxa-4,8-diazaspiro[4.5]dec-4-yl)-3-(1H-indol-3-yl)-propan-1-one) (1,4-dimethyl-6-(3-indolpropionyl)-spiro-(3-oxa-6-aza-bicyclo[3.1.]-hexane-2,4 -piperidine)) (1,4-dimethyl-6-[3-(4-fluorobenzenesulfonyl)]-spiro-(3-oxa-6-aza-bicycl 0[3.1.0]hexane-2,4-piperidine)) N-(2,8-dimethyl-1-oxa-8-aza-spiro[4.5]dec-3-yl)-3-(1H-indol-3-yl)-propionamide N-(2,8-Dimethyl-1-thia-8-aza-spiro[4.5]dec-3-yl)-3-(1H-indol-3-yl)-propionamide, and (3E)-2,8-dimethyl-1-oxa-8-aza-spiro[4.5]decan-3-one-O-[3-(1H-indol-3-yl)propanoyI]oxime.
