Posted by yxibow on February 24, 2008, at 7:48:01
In reply to Dopamine receptor antagonists, posted by Jamal Spelling on February 23, 2008, at 16:00:13
> Dopaminergic and Glutamatergic Regulation of Effort- and Delay-Based Decision Making, Floresco SB, Tse MT, and Ghods-Sharifi S, Neuropsychopharmacology, September 2007.
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> Abstract:
> Cost/benefit decisions regarding the relative effort or delay costs associated with a particular response are mediated by distributed dopaminergic and glutamatergic neural circuits. The present study assessed the contribution of dopamine and NMDA glutamate receptors in these different forms of decision making using novel effort- and delay-discounting procedures. In the effort-discounting task, rats could either emit a single response on a low-reward lever to receive two pellets, or make 2, 5, 10, or 20 responses on a high-reward (HR) lever to obtain four pellets. In the delay-discounting task, one press of the HR lever delivered four pellets after a delay (0.5-8 s). A third task (effort-discounting with equivalent delays) was similar to the effort-discounting procedure, except that the relative delay to reward delivery was equalized across response options. The dopamine receptor antagonist flupenthixol reduced choice of the HR lever under all three testing conditions, indicating that dopamine antagonism alters effort-based decision making independent of any contribution of delay. Amphetamine exerted dose-dependent, biphasic effects; a higher dose (0.5 mg/kg) increased effort discounting, whereas a lower dose (0.25 mg/kg) reduced delay discounting. The noncompetitive NMDA antagonist ketamine (5 mg/kg) increased effort and delay discounting, but did not affect choice on the effort with equivalent delays task, indicating a reduced tolerance for delayed rewards. These findings highlight the utility of these procedures in pharmacologically dissociating the neurochemical mechanisms underlying these different, yet interrelated forms of decision making. Furthermore, they suggest that dopamine and NMDA receptors make dissociable contributions to these different types of cost-benefit analyses.
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> My question is: in the context of what they say about flupenthixol above, what do they mean by "dopamine antagonism alters effort-based decision making independent of any contribution of delay"?Basically from what I can discern this is a rat study that shows that the dopamine blockade in APs reduces confusion and decision making, at least in an animal model.
And in fact, though I am not taking it for its true label, Seroquel does reduce confusion and organizes my thoughts in as best a manner as there is an agent out there that the benefits still outweigh the risks at the moment.
But I'm reading into it myself.
Flupenthixol is a fairly powerful typical agent but occupies D2 slightly less than Haldol. It is used in noncompliant (aggressive, which is usually not the most common display of schizophrenia from what I know of) situations as well, although a number of depot agents including atypicals are available.
poster:yxibow
thread:814286
URL: http://www.dr-bob.org/babble/20080221/msgs/814389.html