PSY305 CH5PT4: Dopamine Function

[@pennyyroyalteaa]

thank you so much the clearest video i found on youtube

[@avaxfuture8282]

Are dopamine d2 receptors inhibitory?

[@pedromachado8513]

yes

[@avaxfuture8282]

@@pedromachado8513 So, Why do we use antipsychotics to block d2 receptors to cure psychosis? I know there is an imbalance between excitatory and inhibitory signals in psychosis. If we suppress the inhibitory receptor to cure psychosis, the reason should be that there is overinactivation. If we block the inhibitory receptor, the response will be in the direction of the excitatory signal. Our treatment of psychosis will cause an excitatory effect.

[@pedromachado8513]

@@avaxfuture8282 i cant answer your question, but i think that receptors d1 to d5 are ALL blocked at least a little

[@avaxfuture8282]

@@pedromachado8513 yes but d1 and d5 are excitatory. And they are blocked to a very small degree with antipsycotics.

[@avaxfuture8282]

​@@pedromachado8513 Maybe, to provide homeostasis, inhibitory d2 receptors are upregulated in psychosis to compensate extreme excitatory signal. On the other hand, excitatory d1 receptors are downregulated to block extreme excitatory signal. But then, why and how do d2 blockers improve symptoms? Maybe when inhibitory d2 receptors are overexpressed to provide homeostatis and compensate extreme excitatory signal, this overinhibition also contribute to symptoms of psychosis. Maybe the final balance (upregulation of d2 and downregulation of d1) set by neurons contribute to symptoms of psychosis. Antipsychotics maybe try to reconvert unhealthy signalling to healthy signalling. So, over upregulation of inhibitory d2 receptors can cause psychotic symptoms. So the question is what is the cause of imbalance? Is it due to the extreme excitatory signal or is it due to the insufficient inhibitory signal? Maybe at the beginning of the psychotic attack, there is extreme excitatory signal. And the inhibitory receptors becomes corrupted when dealing with such extreme conditions. They fail to receive too many signal. When the extreme excitatory signal finishes, the inhibitory receptors are still corrupted and unable to balance. Then normal level of excitatory signals are not balanced by corrupted inhibitory receptors and neurons. So to provide balance, neurons downregulate d1(excitatrory), and upregulate d2 (inhibitory). But this kind of new balance is not healthy. Because to become fully functional, neurons need old version and healthy balance. I guess so.