In the rat, administration of the psychoactive analog of amphetamine 3,4-methylenedioxymethamphetamine (MDMA), causes selective, pronounced decreases in markers of central serotonergic function. The time course of these neurochemical changes was examined in several serotonergic nerve terminal regions of the brain. Fifteen min after subcutaneous injection of MDMA (10 mg/kg), the enzymatic...
Phencyclidine (PCP)-induced behaviors were compared with 5-methoxy-N,N-dimethyltryptamine (5-MeODMT)- and p-chloroamphetamine-induced behaviors in rats pretreated with ritanserin or 5,7-dihydroxytryptamine (5,7-DHT) in order to investigate whether PCP interacts with 5-hydroxytryptamine2 (5-HT2) receptors. Head-twitch and wet-dog shake induced by p-chloroamphetamine, a 5-HT releaser, and...
Phencyclidine mainly produced head-weaving and head-twitches at doses of 5-7.5 mg/kg and of 7.5-12.5 mg/kg, respectively. Phencyclidine-induced head-twitches and head-weaving were blocked by pretreatment with ritanserin (1 mg/kg), a selective serotonin (5-HT)2 receptor antagonist and with pindolol (20 mg/kg, s.c.), a 5-HT1 receptor antagonist, respectively. In reserpine-pretreated rats, the...
This study examines the effects of repeated systemic administration (20 mg/kg s.c., twice daily for 4 days) of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) on levels of brain monoamines, their metabolites and on the density of monoamine uptake sites in various regions of rat brain. Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid...
The present experiments served to compare the effects of the 3 5-HT1 agonists, 8-OH-DPAT, 5-MeODMT and TFMPP on the blood pressure and heart rate of normotensive anaesthetized rats. All the agonists induced, after i.v. injection, a decrease in blood pressure and heart rate. The hypotensive effects of 5-MeODMT and TFMPP were preceded by an increase, suppressed by both ketanserin and...
A group of ten rats was trained to obtain food pellets in an 8-arm radial maze. The effects of pretreatment with (+)-Lysergic acid diethylamide (+)-tartrate (LSD), m-trifluoromethylphenylpiperazine (TFMPP), 5-methoxy-N,N-dimethyltryptamine oxalate (5-MeO-DMT), racemic 8-hydroxy-2-(di-n-propylamino)tetralin HBr (8-OH-DPAT), and 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole succinate (RU...
This study was designed to assess whether phencyclidine (PCP)-induced head-twitch was antagonized by ritanserin, a selective serotonin (5-HT2) receptor antagonist, in mice and rats to confirm the involvement of 5-hydroxytryptamine (5-HT) neurons in PCP actions in comparison with 5-methoxy-N,N-dimethyltryptamine (5-MeODMT)-induced behavior. PCP (7.5, 10 and 12.5 mg/kg, i.p.)-induced head-twitch...
3H-(+/-)-4-Bromo-2,5-dimethoxyphenylisopropylamine (3H-DOB), a putative agonist radioligand, was synthesized and used to label 5-HT2 receptors in a particulate fraction prepared from rat frontal cortex tissue homogenates. The specific binding (defined by the difference in 3H-DOB binding in the presence and absence of 10(-6) M cinanserin, a potent and specific 5-HT2 antagonist) displayed high...
Abstract N1‐([ 11 C]‐Methyl)‐2‐Br‐LSD ([ 11 C]‐MBL) has been developed as a positron emission tomography (PET) imaging agent for serotonin 5‐HT 2 receptors. In vitro receptor binding assays with nonradioactive MBL show high‐affinity binding to serotonin 5‐HT 2 receptors (K i = 0.5 nM), a secondary interaction of 8‐fold lower affinity with dopamine D 2 receptors, and low‐affinity interactions...
The effect of the selective 5-HT3 receptor antagonists ICS 205-930 and MDL 72222 on head shaking behavior induced by L-5-HTP and behavioral symptoms induced with 5-methoxy-N,N,-dimethyltryptamine (5-MeODMT) in rats was evaluated. Both drugs dose-dependently reduced L-5-HTP-induced head shaking but were at least 600 times less potent than pirenperone and ketanserin and at least 50 times less...