The effects in vitro of 1-(1-phenylcyclohexyl) piperidine hydrochloride (sernyl) on oxidation by liver homogenates and mitochondria of rat

Factors in the lethality of i.v. phencyclidine in conscious dogs

1. Pretreatment were pancuronium prevented convulsions and hyperthermia, but had no effect on acidemia or changes in cardiovascular parameters after intravenous (i.v.) infusion of phencyclidine (PCP). 2. While dogs survived higher amounts of PCP, they failed to regain spontaneous respiratory function. 3. Mechanical ventilation alone increased the mean lethal dose/time of PCP and reduced the effects of PCP on arterial systolic pressure, cardiac output, and PCO2. 4. EKG showed ventricular arrhythmias, which progressed to death. 5. Phenytoin pretreatment plus respiratory assistance increased the lethal dose and reduced PCP effects on cardiovascular parameters, body temperature, and cardiac rhythm. 6. Blocking of convulsions prevented hyperthermia and acidemia; respiratory support reduced circulatory effects, but respired dogs then died, at higher doses, from a primary myocardial toxicity of PCP.

Phencyclidine. Physiological actions, interactions with excitatory amino acids and endogenous ligands

Phenycyclidine (PCP) produces many profound effects in the central nervous system. PCP has numerous behavioral and neurochemical effects such as inhibiting the uptake and facilitating the release of dopamine, serotonin, and norepinephrine. PCP also interacts with sigma, mu opioid, muscarinic, and nicotinic receptors. However, the psychotomimetic effects induced by PCP are believed to be mediated by specific PCP receptors, where PCP binds with greater potency than sigma compounds. Electrophysiological, behavioral, and neuro-chemical evidence strongly suggests that at least some of the many PCP actions result from antagonism of excitatory amino acid-induced responses via PCP receptors. The recent isolation and partial characterization of the alpha and beta endopsychosins and the identification of other endogenous ligands for the PCP and sigma receptors, is another promising area of research in the elucidation of the physiological role of an endogenous PCP and sigma system.

Effect of phencyclidine on the metabolism of individual brain proteins

The effect of phencyclidine on the metabolism of a selected number of rat brain proteins was determined using two-dimensional gel electrophoresis and quantitative fluorography. When rats were injected with phencyclidine, modulation of individual protein metabolism occurred in the pituitary and cortex. That is, a few proteins showed increased and others decreased incorporation of [35S]methionine, whereas total protein metabolism was unaltered. In contrast, in vitro treatment of brain tissue with phencyclidine inhibited incorporation of radiolabel into all proteins by approximately 50%, as shown by quantitative fluorography of individual proteins.

Phencyclidine and analogues: effects on brain protein synthesis

Phencyclidine and four analogues were tested for their capacity to inhibit total protein synthesis in a brain homogenate. At 1.0 mM they were all found to be potent inhibitors with values ranging from 36% to 96% inhibition. At this high concentration two of the analogues were equal to or more effective than the classic protein synthesis inhibitors cycloheximide and emetine. At lower concentrations the inhibition dropped off sharply to 18% at 1.0 X 10(-4) M and 9% at 1.0 X 10(-5) M for phencyclidine. If the inhibition observed in the brain homogenate occurs in vivo it may account for the high incidence of memory loss reported with phencyclidine use.

Acute phencyclidine poisoning in the unanesthetized dog: pathophysiologic profile of acute lethality

Phencyclidine HCl was infused intravenously (1.0 mg/kg/min) to unanesthetized mongrel dogs until death. All animals experienced tonic-clonic convulsions (mean convulsive dose: 4.7 +/- 0.3 mg/kg) which lasted until shortly before death (mean lethal dose: 49.8 +/- 2.5 mg/kg). Significant increases in heart rate, arterial blood pressures, cardiac output, body temperature, and arterial pCO2 were observed in all animals. Significant reductions from pre-drug control values were observed in total peripheral resistance, arterial pH, arterial pO2, and respiratory minute volume. Blood lactate, oxygen uptake, and plasma glucose levels rose to values significantly higher than pre-drug control values then declined during the latter phase of the experiment, glucose levels decreased to final values lower than control. Animals appeared to die of primary respiratory failure, which was exacerbated by hyperthermia, and which resulted in final cardiovascular collapse.