Andrew Derrick GlaxoSmithKline Gribble

SB-656104-A, a novel selective 5-HT7 receptor antagonist, modulates REM sleep in rats

(6‐((R)‐2‐{2‐[4‐(4‐Chloro‐phenoxy)‐piperidin‐1‐yl]‐ethyl}‐pyrrolidine‐1‐sulphonyl)‐1H‐indole hydrochloride) (SB‐656104‐A), a novel 5‐hydroxytryptamine (5‐HT7) receptor antagonist, potently inhibited [3H]‐SB‐269970 binding to the human cloned 5‐HT7(a) (pKi 8.7±0.1) and 5‐HT7(b) (pKi 8.5±0.2) receptor variants and the rat native receptor (pKi 8.8±0.2). The compound displayed at least 30‐fold selectivity for the human 5‐HT7(a) receptor versus other human cloned 5‐HT receptors apart from the 5‐HT1D receptor (∼10‐fold selective). SB‐656104‐A antagonised competitively the 5‐carboxamidotryptamine (5‐CT)‐induced accumulation of cyclic AMP in h5‐HT7(a)/HEK293 cells with a pA2 of 8.5. Following a constant rate iv infusion to steady state in rats, SB‐656104 had a blood clearance (CLb) of 58±6 ml min−1 kg−1 and was CNS penetrant with a steady‐state brain : blood ratio of 0.9 : 1. Following i.p. administration to rats (10 mg kg−1), the compound displayed a t1/2 of 1.4 h with mean brain and blood concentrations (at 1 h after dosing) of 0.80 and 1.0 μM, respectively. SB‐656104‐A produced a significant reversal of the 5‐CT‐induced hypothermic effect in guinea pigs, a pharmacodynamic model of 5‐HT7 receptor interaction in vivo (ED50 2 mg kg−1). SB‐656104‐A, administered to rats at the beginning of the sleep period (CT 0), significantly increased the latency to onset of rapid eye movement (REM) sleep at 30 mg kg−1 i.p. (+93%) and reduced the total amount of REM sleep at 10 and 30 mg kg−1 i.p. with no significant effect on the latency to, or amount of, non‐REM sleep. SB‐269970‐A produced qualitatively similar effects in the same study. In summary, SB‐656104‐A is a novel 5‐HT7 receptor antagonist which has been utilised in the present study to provide further evidence for a role for 5‐HT7 receptors in the modulation of REM sleep.

SB-656104-A: A novel 5-HT7 receptor antagonist with improved In vivo properties

A focused SAR study around the previously reported selective 5-HT(7) receptor antagonist, SB-269970-A has resulted in the identification of a structurally related analogue having an improved pharmacokinetic profile. Replacement of the phenolic group in SB-269970-A with an indole moiety, and replacement of the piperidinyl 4-methyl group with a heterocyclic ring system proved to be the key changes leading to the identification of SB-656104-A.

Conformationally restricted indolopiperidine derivatives as potent CCR2B receptor antagonists

The preparation and biological evaluation of a series of indolopiperidine CCR2B receptor antagonists possessing a conformationally restricted C-5 linker chain in combination with a restricted piperidine ring are described. Compared to the parent compound 1, analogue 8 shows a dramatic improvement in selectivity against a range of 5-HT and dopaminergic receptors.

Pharmacological Profile of Antipsychotics at Monoamine Receptors: Atypicality Beyond 5-HT2A Receptor Blockade

Antipsychotic drugs (APD) are widely prescribed for the treatment of schizophrenia. The APD are differentiated into typical and atypical based on the lower incidence of extra-pyramidal side-effects associated with the newer atypical APD. It was suggested that atypicality may arise from an interaction with the 5-hydroxytryptamine (5-HT)(2) receptor and specifically on the 5-HT(2):dopamine D(2) affinity ratio. It is now realised that multiple subtypes of these receptors exist and that in addition, atypical APD interact with many monoamine receptors. The aim of the present study was to characterise the interaction of APD with a variety of monoamine receptors in terms of both affinity and efficacy. The data produced has highlighted that the atypical profile of APD such as olanzapine and clozapine may reflect antagonism of the 5-HT(2A) and 5-HT(2C) receptors, whilst that of, ziprasidone and quetiapine may reflect partial agonist activity at the 5-HT(1A) receptor, and that of aripiprazole may reflect partial agonist activity at the 5-HT(1A) receptor as well as is its claimed partial agonist activity at the dopamine D(2) receptor.

Identification of a novel series of selective 5-HT7 receptor antagonists

Novel 5-HT(7) receptor antagonists containing the benzocycloheptanone core were identified from high throughput screening. Molecular modelling and SAR studies have converted these intractable hits into a more potent, selective and tractable series, exemplified by compound (25), SB-691673.