An in vitro profile of activity for the (+) and (-) enantiomers of spiradoline and PD117302.

Kappa- and mu-opioid binding site affinities of the kappa-selective ligand U62066 and its optical isomers, (+)-U63639 and (-)-U63640 were compared with those of the structurally related ligand PD117302 and its respective isomers, (+)-PD123497 and (-)-PD123475. The relative efficacies of each compound were also established using the guinea-pig ileum, rat and rabbit vas deferens smooth muscle bioassays. The specific opioid receptor mediating the agonist behaviour was determined in the guinea-pig ileum bioassay by obtaining pKB values for naloxone and for the kappa-selective antagonist nor-binaltorphimine.

Effects of cholecystokinin and pentagastrin on rat hippocampal neurones maintained in vitro.

Extracellular and intracellular recordings from CA1 neurones of rat hippocampal slices were undertaken to assess the relative potencies of cholecystokinin fragments. The CCK peptides displayed a large variability in their effects on extracellularly recorded population spikes. Intracellular recordings from CA1 neurones revealed a more consistent excitant action of these compounds.