IBMX

IBMX is a widely-used non-specific inhibitor of phosphodiesterase (PDE) with IC50 values of 6.5±1.2, 26.3±3.9 and 31.7±5.3 μM for PDE3, 4 and 5 respectively[1]. 

By inhibiting PDEs, IBMX increases cellular cAMP and cGMP levels, activating cyclic-nucleotide-regulated protein kinases. Methylxanthines, including IBMX, caffeine, and theophylline, bind adenosine receptors, typically antagonizing the suppressive effects of natural agonists[2]. 

Sprague–Dawley rats receive an i.c.v. injection(IBMX or saline) 10 min before receiving an i.p. injectionof cocaine or saline. Intracerebroventricular IBMX does not affect the acute hyperlocomotor responseto cocaine, but when coadministered with cocaine for 7 consecutive days, attenuated development ofbehavioral sensitization. These results suggest that IBMX inhibition of PDE-mediated adenosine production[3]. 

References:

[1]. Wu BN, et al. KMUP-1, a xanthine derivative, induces relaxation of guinea-pig isolated trachea: the role of the epithelium, cyclic nucleotides and K+ channels. Br J Pharmacol, 2004, 142(7): 1105-14.

[2]. Snyder S H, Katims J J, Annau Z, et al. Adenosine receptors and behavioral actions of methylxanthines. Proc. Natl. Acad. Sci. USA, 1981, 78(5): 3260-3264.

[3]. Schroeder J A, Ruta J D, Gordon J S, et al. The phosphodiesterase inhibitor isobutylmethylxanthine attenuates behavioral sensitization to cocaine. Behavioural Pharmacology, 2012, 23(3): 310-314.