The short answer is "yes". The long answer is "that's a philosophical question".
Downregulation is a natural homeostatic mechanism that happens with almost everything. Any time a certain receptor gets stimulated above baseline, over the long-term it's going to get downregulated. The actual neurobiology of how this works is enormously complicated and beyond my (and probably almost anyone's) understanding. I do recall that NMDA receptors have a critical role to play, given that NMDA receptor antagonists can attenuate some (presumably not all) of the down or up regulation
The short answer is "yes". The long answer is "that's a philosophical question".
Downregulation is a natural homeostatic mechanism that happens with almost everything. Any time a certain receptor gets stimulated above baseline, over the long-term it's going to get downregulated. The actual neurobiology of how this works is enormously complicated and beyond my (and probably almost anyone's) understanding. I do recall that NMDA receptors have a critical role to play, given that NMDA receptor antagonists can attenuate some (presumably not all) of the down or up regulation