Neuropharmacological profile of a high-affinity ligand of 5-HT1A receptors, 4-phenyl-1-[4-(2-naphtalimido)butyl]-piperazine

The neuropharmacological profile of 4-phenyl-1-4-(2-naphtalimido)butyl]-piperazine (PNBP), a compound that possesses a high affinity for the serotonin receptors of 1A-type (5-HT_1A) and lacks an anxiolytic action, has been studied. Intracerebral administration of PNBP to rats through implanted cannulae into the hippocampal region resulted in no substantial behavioral changes during “open field” and “conflict situation” tests, as compared with those of control animals. At the same time, the behavioral effects of intraperitoneal administration of 10 mg/kg buspirone were completely abolished if buspirone had been jointly administered with 10 mg/kg PNBP. Moreover, combined application of 0.3 mg/kg PNBP and 0.3 mg/kg 8-OH-DPAT, an agonist of 5-HT_1A receptors, almost completely abolished the components of “serotonin syndrome” (prone position and stamping of the forepaws) in animals under study. These findings allowed us to conclude that PNBP has the properties of a competitive antagonist of buspirone and 8-OH-DPAT.