Stephan, Thank you for yet another extremely detailed and helpful response. Dr Duvoisins model certainly answers my query regarding apomorphine induced dyskinesia. It also seems to answers another query of mine - which being "why does dyskinesia increase under stress?". My understanding of the model suggests that stress conditions (higher adrenaline levels?) probably raise the sensitivity of the receptors even more. In the words of an old song - "I'm beginning to see the light." Dennis. ++++++++++++++++++++ Dennis Greene 47/10 [log in to unmask] ++++++++++++++++++++