View Full Version : Yohimbine verses guanfacine for impulsivity.


theta
06-06-08, 09:33 PM
I thought this was interesting.

1: Biol Psychiatry. 2005 May 15;57(10):1209-11.
Links
Acute yohimbine increases laboratory-measured impulsivity in normal subjects.
Swann AC, Birnbaum D, Jagar AA, Dougherty DM, Moeller FG.

Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA. Alan.C.Swann@uth.tmc.edu

BACKGROUND: State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders. METHODS: Impulsivity was assessed using the Immediate and Delayed Memory Tasks (IMT-DMT), derived from the Continuous Performance Test, before and after placebo or two doses of yohimbine, given 4 days apart. Blood pressure was monitored, and psychiatric symptoms were measured using self-rated visual analog scales. RESULTS: Yohimbine was associated with a dose-related increase in impulsive IMT commission errors, with an increase of > 50% relative to baseline at the higher dose. The activation factor of the Internal State Scale was increased at the same dose. CONCLUSIONS: These results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.

PMID: 15866563 [PubMed - indexed for MEDLINE]

http://en.wikipedia.org/wiki/Yohimbine

Yohimbine Hydrochloride is a selective competitive alpha2-adrenergic receptor antagonist

Guanfacine and clonidine have the opposite action.

http://en.wikipedia.org/wiki/Alpha2-adrenergic_receptor#Agonists

JR1973
06-09-08, 08:46 AM
Yohimbine has been a long time attempt for ED. Supposedly this chemical can cause havoc with blood pressure too.

J

TygerSan
06-09-08, 11:57 AM
Yep, guanfacine and yohimbine are "opposites" in that guanfacine is an alpha2 agonist (specifically alpha2A), and yohimbine is an antagonist of the same receptor. Guanfacine is a "cleaner" drug than yohimbine (which also can hit other alpha receptors and has effects on imodazaline [sp?] receptors).

Idazoxan (another antagonist like yohimbine) can actually facilitate certain forms of learning and attention, though, so nothing's really cut-and-dried.

evenbalance1
06-22-08, 11:29 PM
yohimbine is good for weight loss BTW! i dont speak from experience, but from scientific PROOF!

theta
06-23-08, 02:48 AM
yohimbine is good for weight loss BTW! i dont speak from experience, but from scientific PROOF!

When theres proof its always good to post a references to that proof.

evenbalance1
06-23-08, 03:26 AM
When theres proof its always good to post a references to that proof.

i know. just too lazy to. i figured if someone was interested they would search on their own. i learned this from lyle mcdonalds rapid fatloss handbook and the book the ketogenic diet

theta
06-23-08, 05:49 AM
The anxiogenic drug yohimbine activates central viscerosensory circuits in rats. (http://www.ncbi.nlm.nih.gov/pubmed/16228990)

Systemic administration of the alpha(2)-adrenoceptor antagonist yohimbine (YO) activates the HPA stress axis and promotes anxiety in humans and experimental animals.

Increases anxiety and impulsivity though.

Systemic YO (5.0 mg/kg BW, i.p.) inhibited food intake

YO administered at 1.0 mg/kg BW did not inhibit food intake

jasica
05-07-09, 12:14 AM
Thanks for taking the time to help, I really apprciate it.

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