Phencyclidine and analogues: effects on brain protein synthesis

Area of Science:

• Neuroscience
• Biochemistry
• Pharmacology

Background:

• Phencyclidine (PCP) is a dissociative anesthetic with known neurotoxic effects.
• Protein synthesis is crucial for neuronal function and memory formation.
• The precise molecular mechanisms underlying PCP-induced neurotoxicity, particularly regarding protein synthesis, remain incompletely understood.

Purpose of the Study:

• To investigate the inhibitory effects of phencyclidine and its analogues on total protein synthesis in brain homogenates.
• To compare the potency of phencyclidine and its analogues as protein synthesis inhibitors with established drugs like cycloheximide and emetine.
• To explore the potential correlation between inhibited protein synthesis and reported memory loss in phencyclidine users.

Main Methods:

• Preparation of rat brain homogenates.
• Incubation of homogenates with phencyclidine and four analogues at varying concentrations (1.0 mM, 1.0 x 10(-4) M, 1.0 x 10(-5) M).
• Measurement of total protein synthesis inhibition using established biochemical assays.

Main Results:

• Phencyclidine and its analogues demonstrated potent inhibition of total protein synthesis in brain homogenates at 1.0 mM, with inhibition ranging from 36% to 96%.
• At 1.0 mM, two analogues were as effective or more effective than cycloheximide and emetine.
• Inhibition decreased significantly at lower concentrations, with phencyclidine showing 18% inhibition at 1.0 x 10(-4) M and 9% at 1.0 x 10(-5) M.

Conclusions:

• Phencyclidine and its analogues possess significant capacity to inhibit brain protein synthesis.
• The observed inhibition of protein synthesis in vitro suggests a potential in vivo mechanism for phencyclidine's neurotoxicity.
• This disruption of protein synthesis may underlie the cognitive deficits, specifically memory loss, frequently reported in phencyclidine users.