Pharmacology, biochemistry, and behavior
October 1999
J C Winter, D J Fiorella, D M Timineri et al.
More than a quarter century has passed since the demonstration that indoleamine and phenethylamine hallucinogens can function as discriminative stimuli in the rat, and that serotonergic systems are critically involved. During that period our knowledge of the physiology, pharmacology, biochemistry, and molecular biology of serotonergic receptors has increased exponentially; with each advance it...
Pharmacology, biochemistry, and behavior
July 1, 1999
Jerrold C Winter, Scott Helsley, David Fiorella et al.
14 citations
In a previous study it was observed that fluoxetine potentiates the stimulus effects of lysergic acid diethylamide (LSD). In the present investigation, stimulus control was established in groups of rats using as training drugs the hallucinogens lysergic acid diethylamide (LSD); 0.1 mg/kg), (-)-2,5-dimethoxy-4-methylamphetamine [(-)-DOM; 0.56 mg/kg], ibogaine (10 mg/kg), and...
Progress in Neuro-psychopharmacology and Biological Psychiatry
May 1, 1998
Scott Helsley, David Fiorella, Richard A. Rabin et al.
30 citations
1. A series of N-substituted tryptamines was compared with a series of beta-carbolines in rats trained to discriminate LSD (0.1 mg/kg) from saline. 2. Intermediate levels of substitution were elicited by MDMT (76.4%), DMT (77.9%), and DET (48.7%). 6-F-DET produced 41.3% LSD-appropriate responding at a dose of 6.0 mg/kg but only 4 of 8 subjects completed the test session thus precluding...
Pharmacology, biochemistry, and behavior
February 1, 1998
Scott Helsley, David Fiorella, R A Rabin et al.
35 citations
In the present investigation, the ability of two known hallucinogens, lysergic acid dimethylamide (LSD) and (-)-2,5-dimethoxy-4-methyl-amphetamine (DOM), to substitute for the ibogaine-induced discriminative stimulus (10 mg/kg I.P., 60 min presession) was assessed in Fischer-344 rats. In these subjects, intermediate levels of generalization were observed to both agents (LSD, 63%; DOM, 66.4%)....
Pharmacology, biochemistry, and behavior
September 1, 1997
Scott Helsley, David Fiorella, R A Rabin et al.
9 citations
The effects of ibogaine were studied in 12 rats trained to perform in an 8-arm radial maze. In Phase I, the mean number of sessions to criterion and cumulative errors to criterion, as well as mean response rate, were determined for two groups of six animals in a task where only four arms were baited. Group 1 received a potentially neurotoxic dose of ibogaine (50 mg/kg IP administered twice,...
Psychopharmacology
December 1995
D Fiorella, S Helsley, R A Rabin et al.
The present study was designed to investigate the hypothesis that agonist interactions at 5-HT2C receptors mediate the discriminative stimulus properties of m-chlorophenylpiperazine (mCPP). Three structural classes of compounds have been described to stimulate increases in phosphoinositide (PI) hydrolysis at the 5-HT2C receptor site: phenylpiperazines, phenylalkylamines, and indolamines. Four...
Psychopharmacology
October 1995
D Fiorella, R A Rabin, J C Winter
Investigations conducted over the past 3 decades have demonstrated that serotonergic receptors, specifically the 5-HT2A and 5-HT2C subtypes, play an important role in the behavioral effects of hallucinogenic compounds. The present study was designed to determine the respective significance of these two receptors in the stimulus effects of LSD and (-)DOM in the rat. Specifically, the...
Psychopharmacology
October 1995
D Fiorella, S Helsley, D S Lorrain et al.
The present study was designed to determine the effects of p-chlorophenylalanine (PCPA) and p-chloroamphetamine (PCA) administration on (1) the levels of serotonin (5-hydroxytryptamine, 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in rat brain, (2) the sensitivity of LSD-trained rats to the stimulus effects of LSD, and (3) the maximal levels of 5-HT2A and 5-HT2C receptor mediated...
Neuropharmacology
October 1995
D Fiorella, S Helsley, R A Rabin et al.
The present study was designed to test the hypothesis that atypical, but not typical, antipsychotics produce a functional in vivo blockade of 5-HT2A receptors. The magnitude of functional in vivo 5-HT2A receptor blockade elicited by representative compounds from each of the six major structural classes of typical antipsychotics, and the representative atypical antipsychotics clozapine and...
Psychopharmacology
October 1995
D Fiorella, R A Rabin, J C Winter
In the context of animal studies of hallucinogens, an LSD-false positive is defined as a drug known to be devoid of hallucinogenic activity in humans but which nonetheless fully mimics LSD in animals. Quipazine, MK-212, lisuride, and yohimbine have all been reported to be LSD false positives. The present study was designed to determine whether these compounds also substitute for the stimulus...
Psychopharmacology
May 1995
D Fiorella, P A Palumbo, R A Rabin et al.
The pharmacodynamic characteristics of the stimulus effects of the hallucinogens d-LSD and (-)DOM were investigated in the rat. The stimulus control induced by (-)DOM (0.56 mg/kg) was significantly less stable at the 15-min pretreatment time than at the 75-min pretreatment time. In addition, (-)DOM (0.8 mg/kg) produced a time-dependent substitution for the LSD stimulus in LSD trained subjects...