Posted by Cam W. on September 17, 2001, at 7:46:12
In reply to Differences in action Dopamine and Norepinephrine?, posted by jay on September 17, 2001, at 6:55:50
Jay -
Dopamine - binds to 2 families of dopamine receptors: D1 (D1 & D5 - mainly presynaptic) and D2 (D2, D3, & D4 - mainly postsynaptic).
- affects drive, pleasure, and euphoria; also involved in cognitive integration, working memory, and the initiation of motor activity.
- stimulation of dopamine receptors can cause agitation (D3) and aggravation of psychosis (D2).
- irreversible blockade of D2 receptors ( >70%) can cause EPS and tardive dyskinesia.
- blockade of D3 receptors may play a role in the anti-anxiety/antidepressant action of Fluanxol™ (flupenthixol), an antipsychotic.•••••
Norepinephrine - binds to alpha-1, ß1 presynaptic (& somatodendritic?) and alpha-2, ß2 postsynaptic receptors.
- affects energy, interest, viligence, and self-perception; also involved in sleep maintenance and mood modulation.
- stimulation of norepinephrine receptors can cause activation, hypertension, and panic.
- alpha-1 blockade can cause drowsiness, dizziness, and hypotension.
- ß2 downregulation "may" be a step in the resolving of depressive symptoms, and "may" indirectly decrease cortisol levels by affecting CRF release from the hypothalamus &/or ACTH release from the pituitary (&/or by it's action on release of other neurotransmitters &/or neuromodulators).
- certain antihypertensives and cardiovascular drugs can precipitate or "cause" depression: digitalis, clonidine, guanethidine, methyldopa, reserpine, hydralazine, propranolol, indapamide, prazocin, procainamide, etc.•••••
As for playing with neurotransmitters, researchers will probably have better luck in "fixing" aberrant second messenger systems &/or regulating certain unique gene transcription factors or transcription products (eg. cytokines).
I hope that this is of some help. - Cam
poster:Cam W.
thread:78909
URL: http://www.dr-bob.org/babble/20010917/msgs/78912.html