CGP 13501 is a positive allosteric modulator of GABAB receptor [1].
The GABAB receptor is a metabotropic transmembrane receptors for GABA that is linked via G-protein to potassium channel. It stimulates the opening of K+ channel and hyperpolarize the neuron.
CGP 13501 is a positive allosteric modulator of GABAB receptor. In Chinese hamster ovary (CHO) cell line expressing GABAB(1b/2), CGP 13501 potentiated GABA-stimulated GTPγ[35S] binding to cell membranes [1]. In rat cortex, CGP13501 (10 μM) enhanced GABA-mediated activation of Gαo and increased GTPγ[35S] binding in the presence of GABA. Also, in the hippocampus and cerebellum, CGP13501 increased GABA-induced GTPγ[35S] binding and activation of Gαo. In rat cortex, hippocampus and cerebellum, CGP55845A blocked the influence of CGP13501 on GABA-induced GTPγ[35S] binding at Gαo with pIC50 values of 7.4, 7.31 and 6.82, respectively. In cells expressing GABAB(1b+2) receptors, CGP13501 increased GTPγ[35S] binding at Gαi1/3 [2].
References:
[1]. Urwyler S, Mosbacher J, Lingenhoehl K, et al. Positive allosteric modulation of native and recombinant gamma-aminobutyric acid(B) receptors by 2,6-Di-tert-butyl-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) and its aldehyde analog CGP13501. Mol Pharmacol, 2001, 60(5): 963-971.
[2]. Rasheed N, Ahmad A, Al-Sheeha M, et al. Neuroprotective and anti-stress effect of A68930 in acute and chronic unpredictable stress model in rats. Neurosci Lett, 2011, 504(2): 151-155.