CNS Drug Rev. 2006 Spring;12(1):21-38.
Pharmacological Profile of the Selective FAAH Inhibitor KDS-4103 (URB597).
Piomelli D, Tarzia G, Duranti A, Tontini A, Mor M, Compton TR, Dasse O, Monaghan EP, Parrott JA, Putman D.
Kadmus Pharmaceuticals, Inc. Irvine, California, USA.
In the present article, we review the pharmacological properties of KDS-4103 (URB597), a highly potent and selective inhibitor of the enzyme fatty-acid amide hydrolase (FAAH), which catalyzes the intracellular hydrolysis of the endocannabinoid anandamide. In vitro, KDS-4103 inhibits FAAH activity with median inhibitory concentrations (IC(50)) of 5 nM in rat brain membranes and 3 nM in human liver microsomes. In vivo, KDS-4103 inhibits rat brain FAAH activity after intraperitoneal (i.p.) administration with a median inhibitory dose (ID(50)) of 0.15 mg/kg. The compound does not significantly interact with other cannabinoid-related targets, including cannabinoid receptors and anandamide transport, or with a broad panel of receptors, ion channels, transporters and enzymes. By i.p. administration to rats and mice KDS-4103 elicits significant, anxiolytic-like, antidepressant-like and analgesic effects, which are prevented by treatment with CB1 receptor antagonists. By contrast, at doses that significantly inhibit FAAH activity and substantially raise brain anandamide levels, KDS-4103 does not evoke classical cannabinoid-like effects (e.g., catalepsy, hypothermia, hyperphagia), does not cause place preference, and does not produce generalization to the discriminative effects of the active ingredient of cannabis, Delta9-tetrahydrocannabinol (Delta9-THC). These findings suggest that KDS-4103 acts by enhancing the tonic actions of anandamide on a subset of CB(1) receptors, which may normally be engaged in controlling emotions and pain. KDS-4103 is orally available in rats and cynomolgus monkeys. Sub-chronic repeated dose studies (1500 mg/kg, per os) in these two species have not demonstrated systemic toxicity. Likewise, no toxicity was noted in bacterial cytotoxicity tests in vitro and in the Ames test. Furthermore, no deficits were observed in rats on the rotarod test after acute i.p. treatment with KDS-4103 at doses up to 5 mg/kg or in a functional observation battery after oral doses up to 1500 mg/kg. The results suggest that KDS-4103 will offer a novel approach with a favorable therapeutic window for the treatment of anxiety, depression and pain.
(This worries me re. acomplia.... I just don't see why there shouldn't be some who just crash, big-time, into depression. I must be missing something.)
J Pharmacol Exp Ther. 2006 Jul 10; [Epub ahead of print]
Role for Neuronal Nitric Oxide Synthase in Cannabinoid-induced Neurogenesis.
Kim SH, Won SJ, Mao XO, Ledent C, Jin K, Greenberg DA.
Buck Institute for Age Research.
Cannabinoids, acting through the CB1 cannabinoid receptor (CB1R), protect the brain against ischemia and related forms of injury. This may involve inhibiting the neurotoxicity of endogenous excitatory amino acids and downstream effectors, such as nitric oxide (NO). Cannabinoids also stimulate neurogenesis in the adult brain through activation of CB1R. Because NO has been implicated in neurogenesis, we investigated whether cannabinoid-induced neurogenesis, like cannabinoid neuroprotection, might be mediated through alterations in NO production. Accordingly, we measured neurogenesis in dentate gyrus (DG) and subventricular zone (SVZ) of CB1R-knockout (CB1R-KO) and wild-type mice, some of whom were treated with the cannabinoid agonist 4,5-dihydro-2-methyl-4(4-morpholinylmethyl)-1-(1-naphthalenyl-carbonyl)-6H-pyrrolo[3,2,1-i,j]quinolin-6-one (R(+)-Win 55212-2) or the NO synthase (NOS) inhibitor 7-nitroindazole. NOS activity was increased by ~25%, whereas bromodeoxyuridine (BrdU) labeling of newborn cells in DG and SVZ was reduced by ~50%, in CB1R-KO compared to wild-type mice. 7-NI increased BrdU labeling in both DG and SVZ, and to a greater extent in CB1R-KO than in wild-type mice. In addition, R(+)-Win 55212-2 and 7-NI enhanced BrdU incorporation into neuron-enriched cerebral cortical cultures to a similar maximal extent, and in non-additive fashion, consistent with a shared mechanism of action. Double-label confocal microscopy showed coexpression of BrdU and the neuronal lineage marker doublecortin (Dcx) in DG and SVZ of untreated and 7-NI-treated CB1R-KO mice, and 7-NI increased the number of Dcx- and BrdU/Dcx- immunoreactive cells in SVZ and DG. Thus, cannabinoids appear to stimulate adult neurogenesis by opposing the anti-neurogenic effect of NO.
heh, heh..... Buck Institute and CB1 agonists..... what a surprise! not. |
