PD 176252--the first high affinity non-peptide gastrin-releasing peptide (BB2) receptor antagonist

In this paper we describe the development of a novel series of non-peptide, "balanced" neuromedin-B preferring (BB1)/gastrin-releasing peptide preferring (BB2) receptor ligands as exemplified by PD 176252. PD 176252, which exhibits nanomolar affinity for both the BB1 (Ki = 0.15 nM) and BB2 (Ki = 1.0 nM) receptors, has been demonstrated to be a competitive antagonist at these bombesin receptor subtypes.

Antidiabetic sulphonylureas stimulate acetylcholine release from striatal cholinergic interneurones through inhibition of K(ATP) channel activity

The sulphonylureas tolbutamide and glibenclamide were shown to stimulate acetylcholine release from rat striatal slices. To determine the mechanism of this effect, whole-cell patch-clamp recordings were made from large neurones within the striatum that displayed morphological, electrophysiological, and pharmacological characteristics typical of cholinergic interneurones. Dialysis of these neurones with a pipette solution containing low concentrations of ATP produced a gradual hyperpolarisation that could be reversed by bath application of the sulphonylureas. In voltage-clamp studies, these compounds were shown to act through the inhibition of a potassium conductance. It is concluded that cholinergic interneurones within the rat striatum express sulphonylurea-sensitive ATP-sensitive potassium channel activity. These channels are probably cytoprotective and may prove to be novel sites of therapeutic modulation.