WLB-87848, a Selective σ Receptor Agonist, with an Unusually Positioned NH Group as Positive Ionizable Moiety and Showing Neuroprotective Activity.

The synthesis and pharmacological activity of a new series of thieno[2,3-]pyrimidin-4(3)-one derivatives as sigma-1 receptor (σR) ligands are reported. A hit from a high-throughput screening program was evolved into a highly potent and selective σR agonist () that contains a free NH group as positive ionizable moiety, not fulfilling the usual pharmacophoric features of the σR. The compound shows good physicochemical and ADMET characteristics, displays an agonist profile in the binding immunoglobulin protein/σR association assay, induces neuron viability in an in vitro model of β-amyloid peptide intoxication, and presents positive results against recognition memory impairment induced by hippocampal injection of Aβ peptide in rats after oral treatment, altogether making (WLB-87848) an interesting candidate for neuroprotection.

Towards Multitargeted Ligands as Pain Therapeutics: Dual Ligands of the Caα2δ-1 Subunit of Voltage-Gated Calcium Channel and the μ-Opioid Receptor.

The synthesis and pharmacological activity of a new series of dual ligands combining activities towards the α2δ-1 subunit of voltage-gated calcium channels (Caα2δ-1) and the μ-opioid receptor (MOR) as novel pain therapeutics are reported. A careful exploration of the pharmacophores related to both targets, which in principle had few common characteristics, led to the design of novel compounds exhibiting both activities. The construction of the dual ligands started from published Caα2δ-1 ligands, onto which MOR ligand pharmacophoric elements were added.

Piperazinyl Bicyclic Derivatives as Selective Ligands of the α2δ-1 Subunit of Voltage-Gated Calcium Channels.

The synthesis and pharmacological activities of a new series of piperazinyl quinazolin-4-(3)-one derivatives acting toward the α2δ-1 subunit of voltage-gated calcium channels (Caα2δ-1) are reported. Different positions of a micromolar HTS hit were explored, and best activities were obtained for compounds containing a small alkyl group in position 3 of the quinazolin-4-(3)-one scaffold and a 3-methyl-piperazin-1-yl- or 3,5-dimethyl-piperazin-1-yl-butyl group in position 2. The activity was shown to reside in the enantiomer of the chain in position 2, and several eutomers reached single digit nanomolar affinities.

Propionamide Derivatives as Dual μ-Opioid Receptor Agonists and σ Receptor Antagonists for the Treatment of Pain.

A new series of propionamide derivatives was developed as dual μ-opioid receptor agonists and σ receptor antagonists. Modification of a high-throughput screening hit originated a series of piperazinylcycloalkylmethyl propionamides, which were explored to overcome the challenge of achieving balanced dual activity and convenient drug-like properties. The lead compound identified, , showed good analgesic effects in several animal models of both acute (paw pressure) and chronic (partial sciatic nerve ligation) pain, with reduced gastrointestinal effects in comparison with oxycodone.

Bicyclic Diazepinones as Dual Ligands of the α2δ-1 Subunit of Voltage-Gated Calcium Channels and the Norepinephrine Transporter.

The synthesis and pharmacological activity of a new series of bicyclic diazepinones with dual activity toward the α2δ-1 subunit of voltage-gated calcium channels (Caα2δ-1) and the norepinephrine transporter (NET) are reported. Exploration of the positions amenable for substitution on a nonaminoacidic Caα2δ-1 scaffold allowed the identification of favorable positions for the attachment of NET pharmacophores. Among the patterns explored, attachment of the 2-ethylamino-9-methyl-6-phenyl-6,7,8,9-tetrahydro-5-pyrimido[4,5-][1,4]diazepin-5-one framework to the meta-position of the phenyl ring of the 3-methylamino-1-phenylpropoxy and 3-methylamino-1-thiophenylpropoxy moieties provided dual compounds with excellent NET functionality.

Outside-in regulation of the readily releasable pool of synaptic vesicles by α2δ-1.

The readily releasable pool (RRP) of synaptic vesicles is a key determinant of phasic neurotransmission. Although the size of the RRP is tightly regulated by intracellular factors, there is little evidence for its modification by extracellular signals. By studying the homogeneous population of synapses present in autaptic microcultures, we show that pregabalin, a prototypical gabapentinoid, decreases the effective RRP size.

Pyrazolo[3,4-]pyrimidines as sigma-1 receptor ligands for the treatment of pain. Part 2: Introduction of cyclic substituents in position 4.

The replacement of acylamino by cyclic substituents in the position 4 of the pyrazolo[3,4-]pyrimidine scaffold, led to highly active sigma-1 receptor (σR) ligands. Phenyl or pyrazolyl groups were the best in terms of affinity for the σR and the 4-(1-methylpyrazol-5-yl) derivative, , was the most selective. Compound is also one of the best σR ligands ever described in terms of lipophilic ligand efficiency, which translates into a good physicochemical and ADMET profile.

Pyrazolo[3,4-]pyrimidines as sigma-1 receptor ligands for the treatment of pain. Part 1: 4-acylamino derivatives.

The synthesis of a new series of 4-acylaminopyrazolo[3,4-]pyrimidines active on the sigma-1 receptor (σR) is reported. Compounds were efficiently prepared using a two to three step process starting from commercially available 1-pyrazolo[3,4-]pyrimidin-4-amine. A SAR study shows that the σR requires the presence of relatively highly lipophilic substituents at opposite sides of the central scaffold, while selectivity the σR can be improved by shortening the distance of the basic nitrogen to it.

Generation and phenotypic analysis of sigma receptor type I (sigma 1) knockout mice.

Sigma (sigma) sites are a type of nonopiate receptor whose role has been associated with several behaviours, including anxiety, depression, analgesia, learning processes and psychosis. Although there are several known sigma receptor types, only the type I receptor (sigma 1) has been cloned. To uncover the in vivo relevance of sigma-receptors, we have generated knockout mice for sigma 1.