Biomedical subjects

M D Swedberg

Publications and source records attributed to M D Swedberg.

At least 19 recordsLinked to original sources

PubMed2001

Synthesis of novel gamma-aminobutyric acid (GABA) uptake inhibitors. 5.(1) Preparation and structure-activity studies of tricyclic analogues of known GABA uptake inhibitors.

On the basis of the SAR of a series of known gamma-aminobutyric acid (GABA) uptake inhibitors, including 4 (SKF 89976), new tricyclic analogues have been prepared. These novel compounds are derivatives of nipecotic acid, guvacine, and homo-beta-proline, substituted at the nitrogen of these amino acids by various lipophilic moieties such as (10,11-dihydro-5H-dibenz[b,f]azepin-5-yl)alkoxyalkyl or (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)alkoxyalkyl. The in vitro values for inhibition of [(3)H]-GABA uptake in rat synaptosomes was determined for each compound in this new series, and it was found that several of the novel compounds showed a high potency comparable with that of the reference compounds 4, 5 (tiagabine), and 6 (CI-966). Several of the novel compounds were also evaluated for their ability in vivo to inhibit clonic seizures induced by a 15 mg/kg (ip) dose of methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM). One compound, (R)-1-(2-(2-(10,11-dihydro-5H-dibenz[b,f]azepin-5-yl)ethoxy)ethyl)-3-piperidinecarboxylic acid (23), was selected for further biological investigations and showed a protective index comparable to or slightly better than that of the recently launched anticonvulsant product 5 ((R)-1-(4,4-bis(3-methyl-2-thienyl)-3-butenyl)-3-piperidinecarboxylic acid).

Animals↗

PubMed2001

The muscarinic receptor agonist BuTAC, a novel potential antipsychotic, does not impair learning and memory in mouse passive avoidance.

(5R,6R)-6-(3-butylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[3.2.1]octane) (BuTAC) is a novel, selective muscarinic receptor ligand with partial agonist mode of action at muscarinic M2 and M4 and antagonist mode of action at M1, M3 and M5 receptor subtypes in cloned cell lines. BuTAC exhibits functional dopamine receptor antagonism despite its lack of affinity for dopamine receptors, and parasympathomimetic effects in mice are produced only at doses well beyond the doses exhibiting the antipsychotic-like effects. In the present study we investigated the effects of BuTAC and the antipsychotic compounds clozapine, sertindole and olanzapine using one trial passive avoidance with mice as a model of learning and memory. Pharmacologically relevant doses of BuTAC and reference antipsychotics were identified, based on inhibition of apomorphine-induced climbing in mice as an assay measuring antidopaminergic potency. When ratios between the minimum effective dose (MED) for impairment of retention in passive avoidance and the MED for inhibition of apomorphine-induced climbing were calculated, BuTAC displayed a high ratio of >10, compared with clozapine (0.3), sertindole (3) and olanzapine (3). These data suggest that BuTAC is a potential novel antipsychotic which may have favourable effects on aspects of learning and memory.

Animals↗

PubMed2001

Synthesis of novel GABA uptake inhibitors. Part 6: preparation and evaluation of N-Omega asymmetrically substituted nipecotic acid derivatives.

In a previous series of potent GABA uptake inhibitors published from this laboratory, we noticed that asymmetry in the substitution pattern of the bis-aromatic moiety in known GABA uptake inhibitors such as 4 [1-(4,4-diphenyl-3-butenyl)-3-piperidinecarboxylic acid] and 5 [(R)-1-(4,4-bis(3-methyl-2-thienyl)-3-butenyl)-3-piperidinecarboxylic acid] was beneficial for high affinity. This led us to investigate asymmetric analogues of known symmetric GABA uptake inhibitors in which one of the aryl groups has been exchanged with an alkyl, alkylene or cycloalkylene moiety as well as other modifications in the lipophilic part. The in vitro values for inhibition of [(3)H]-GABA uptake in rat synaptosomes was determined for each compound, and it was found that several of the novel compounds inhibit GABA uptake as potently as their known symmetrical reference analogues. Several of the novel compounds were also evaluated for their ability to inhibit clonic seizures induced by a 15 mg/kg (ip) dose of methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) in vivo. Some of the compounds, for example 18 [(R)-1-(2-(((1,2-bis(2-fluorophenyl)ethylidene)amino)oxy)ethyl)-3-piperidinecarboxylic acid], show a high in vivo potency and protective index comparable with that of our recently launched anticonvulsant product, 5 [(R)-1-(4,4-bis(3-methyl-2-thienyl)-3-butenyl)-3-piperidinecarboxylic acid], and may therefore serve as second-generation drug candidates.

Animals↗

PubMed2001

Effects of infusion rate of intravenously administered morphine on physiological, psychomotor, and self-reported measures in humans.

Although the rate of onset of a drug effect is commonly believed to contribute to a drug's abuse liability, only a few systematic experimental studies have been conducted examining this notion. The present study determined the profile of physiological, psychomotor, and self-reported effects of infusion rate (a key means of manipulating onset of drug action) of intravenously administered morphine, the prototypical analgesic with a known abuse liability in human participants. Two doses of morphine sulfate (5 and 10 mg/70 kg, i.v.) and a placebo dose (0 mg/70 kg, i.v.) were administered to healthy volunteers under three infusion rates (2 min bolus, 15 min, and 60 min). Faster infusions of morphine produced greater positive subjective effects than slower infusions on visual analog scale measures of good drug effect, drug liking, and high. Faster infusions also resulted in greater self-reported drug effects and opioid agonist effects, without producing significant physiological or psychomotor impairment. Importantly, faster rates of drug infusion produced significantly higher morphine plasma levels than slower rates, and morphine plasma levels followed a similar pattern and timing of peak effect as the self-reported effects of the drug. Moreover, morphine produced dose-dependent increases in self-reported drug effects, opioid agonist effects, and morphine plasma levels in the study. Results suggest that the pharmacokinetic properties of a drug, including the dosage administered and the rate of at which it is administered may function to jointly affect the abuse liability of the drug.

Adolescent↗

PubMed2000

Muscarinic receptor agonists decrease cocaine self-administration rates in drug-naive mice.

(5R,6R)-6-(3-Propylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[ 3.2.1]octane (PTAC) is a selective muscarinic receptor ligand. The compound exhibits high affinity for central muscarinic receptors with partial agonist mode of action at muscarinic M(2) and M(4) and antagonist mode of action at muscarinic M(1), M(3) and M(5) receptor subtypes. The compound was earlier reported to exhibit functional dopamine receptor antagonism in rodents despite its lack of affinity for dopamine receptors. In the present study, we report that PTAC, as well as the muscarinic receptor agonists pilocarpine and oxotremorine, dose-dependently decreased rates of intravenous self-administration (fixed ratio 1) of the indirect dopamine receptor agonist cocaine in drug naive mice. Similar decreases in cocaine self-administration rates were obtained with the dopamine receptor antagonists olanzapine, clozapine, risperidone, fluphenazine and haloperidol. These findings suggest that compounds with partial muscarinic receptor agonist mode of action may be used in the medical treatment of cocaine abuse.

Animals↗

PubMed2000

Xanomeline, an M(1)/M(4) preferring muscarinic cholinergic receptor agonist, produces antipsychotic-like activity in rats and mice.

Xanomeline is an M(1)/M(4) preferring muscarinic receptor agonist which decreased psychotic behaviors in patients with Alzheimer's disease, suggesting that xanomeline might be useful in the treatment of psychotic symptoms in patients with schizophrenia. The purpose of the present studies was, therefore, to compare the pharmacologic profile of xanomeline with that of known antipsychotic drugs. Electrophysiologically, xanomeline, after both acute and chronic administration in rats, inhibited A10 but not A9 dopamine cells in a manner which was blocked by the muscarinic receptor antagonist scopolamine. Behaviorally, xanomeline, like haloperidol, clozapine and olanzapine, blocked dopamine agonist-induced turning in unilateral 6-hydroxydopamine-lesioned rats, as well as apomorphine-induced climbing in mice. However, unlike the dopamine antagonist antipsychotic haloperidol, xanomeline did not produce catalepsy in rats. Moreover, xanomeline, like haloperidol, clozapine and olanzapine, inhibited conditioned avoidance responding in rats, an effect which also was blocked by scopolamine. The present results thus demonstrate that xanomeline has a pharmacologic profile which is similar to that of the atypical antipsychotics clozapine and olanzapine, thus indicating that xanomeline has the potential to be a novel approach in the treatment of psychotic symptoms in patients with schizophrenia.

Alzheimer Disease↗

PubMed1999

Synthesis of novel GABA uptake inhibitors. 4. Bioisosteric transformation and successive optimization of known GABA uptake inhibitors leading to a series of potent anticonvulsant drug candidates.

By bioisosteric transformations and successive optimization of known GABA uptake inhibitors, several series of novel GABA uptake inhibitors have been prepared by different synthetic approaches. These compounds are derivatives of nipecotic acid and guvacine, substituted at the nitrogen of these amino acids by various lipophilic moieties such as diarylaminoalkoxyalkyl or diarylalkoxyalkyl. The in vitro values for inhibition of [(3)H]GABA uptake in rat synaptosomes was determined for each compound, and it was found that the most potent compound from this series, (R)-1-(2-(3,3-diphenyl-1-propyloxy)ethyl)-3-piperidinecarboxyli c acid hydrochloride (29), is so far the most potent parent compound inhibiting GABA uptake into synaptosomes. Structure-activity results confirm our earlier observations, that an electronegative center in the chain connecting the amino acid and diaryl moiety is very critical in order to obtain high in vitro potency. Several of the novel compounds were also evaluated for their ability in vivo to inhibit clonic seizures induced by a 15 mg/kg (ip) dose of methyl 6, 7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM). Some of the compounds tested show a high in vivo potency comparable with that of the recently launched anticonvulsant product 6 ((R)-1-(4, 4-bis(3-methyl-2-thienyl)-3-butenyl)-3-piperidinecarboxylic acid).

Animals↗

PubMed1999

Synthesis of novel GABA uptake inhibitors. 3. Diaryloxime and diarylvinyl ether derivatives of nipecotic acid and guvacine as anticonvulsant agents.

(3R)-1-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]-3-piperidinecarboxylic acid 1 (tiagabine, Gabitril) is a potent and selective gamma-aminobutyric acid (GABA) uptake inhibitor with proven anticonvulsant efficacy in humans. This drug, which has a unique mechanism of action among marketed anticonvulsant agents, has been launched for add-on treatment of partial seizures with or without secondary generalization in patients >12 years of age. Using this new agent as a benchmark, we have designed two series of novel GABA uptake inhibitors of remarkable potency, using a putative new model of ligand interaction at the GABA transporter type 1 (GAT-1) uptake site. This model involves the postulated interaction of an electronegative region in the GABA uptake inhibitor with a positively charged domain in the protein structure of the GAT-1 site. These two novel series of anticonvulsant agents contain diaryloxime or diarylvinyl ether functionalities linked to cyclic amino acid moieties and were derived utilizing the new model, via a series of design steps from the known 4,4-diarylbutenyl GABA uptake inhibitors. The new compounds are potent inhibitors of [(3)H]-GABA uptake in rat brain synaptosomes in vitro, and their antiepileptic potential was demonstrated in vivo by their ability to protect against seizures induced by the benzodiazepine receptor inverse agonist methyl 4-ethyl-6,7-dimethoxy-beta-carboline-3-carboxylate (DMCM) in mice. From structure-activity studies of these new GABA uptake inhibitors, we have shown that insertion of an ether oxygen in conjugation with the double bond in tiagabine (K(i) = 67 nM) improves in vitro potency by 5-fold to 14 nM.

Animals↗

PubMed1999

Muscarinic receptor agonists, like dopamine receptor antagonist antipsychotics, inhibit conditioned avoidance response in rats.

The purpose of our studies was to determine the effects of muscarinic receptor agonists on conditioned avoidance responding in the rat. Rats were trained to avoid or escape an electric shock delivered to the feet in a discrete trial procedure. The muscarinic receptor agonists pilocarpine and [2-ethyl-8-methyl-2,8-diazaspiro(4. 5)decane-1,3-dione] hydrochloride (RS86) and the cholinesterase inhibitor physostigmine all decreased the percentage of avoidance responses at doses that produced less than approximately 30% response failures. Similar results were obtained with the antipsychotic drugs haloperidol, trifluoperazine, chlorpromazine, and clozapine. However, the benzodiazepine anxiolytic diazepam did not decrease avoidance responding up to doses that produced ataxia. On the other hand, oxotremorine and arecoline decreased avoidance responding only by producing response failures, whereas aceclidine produced intermediate changes. The muscarinic receptor antagonists scopolamine, trihexyphenidyl, and benztropine were without effect when administered alone but antagonized the decreases in avoidance responding produced by pilocarpine and RS86. Scopolamine had little effect on the decreases in avoidance responding produced by haloperidol. The newer muscarinic receptor partial agonists or agonist/antagonists [R-(Z)-(+)-alpha-(methoxyimino)-1-azabicyclo[2.2. 2]octane-3-acetonitrile] hydrochloride, talsaclidine, milameline, and xanomeline also produced dose-related decreases in avoidance responding. Our results demonstrate that muscarinic receptor agonists can decrease avoidance responding in a manner similar to dopamine-receptor antipsychotic drugs, suggesting that muscarinic receptor agonists may provide an alternative approach to the treatment of psychosis.

Animals↗

PubMed1998

Muscarinic agonists with antipsychotic-like activity: structure-activity relationships of 1,2,5-thiadiazole analogues with functional dopamine antagonist activity.

Muscarinic agonists were tested in two models indicative of clinical antipsychotic activity: conditioned avoidance responding (CAR) in rats and inhibition of apomorphine-induced climbing in mice. The standard muscarinic agonists oxotremorine and pilocarpine were both active in these tests but showed little separation between efficacy and cholinergic side effects. Structure-activity relationships of the alkylthio-1,2,5-thiadiazole azacyclic type muscarinic partial agonists are shown, revealing the exo-6-(3-propyl/butylthio-1,2, 5-thiadiazol-4-yl)-1-azabicyclo[3.2.1]octane analogues (4a,b and 9a, b) to be the most potent antipsychotic agents with large separation between efficacy and cholinergic side effects. The lack of enantiomeric selectivity suggests the pharmacophoric elements are in the mirror plane of the compounds. A model explaining the potency differences of closely related compounds is offered. The data suggest that muscarinic agonists act as functional dopamine antagonists and that they could become a novel treatment of psychotic patients.

Animals↗

PubMed1998

Unexpected antipsychotic-like activity with the muscarinic receptor ligand (5R,6R)6-(3-propylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[3.2.1]octane .

(5R,6R)6-(3-propylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[3 .2.1]octane (PTAC) is a potent muscarinic receptor ligand with high affinity for central muscarinic receptors and no or substantially less affinity for a large number of other receptors or binding sites including dopamine receptors. The ligand exhibits partial agonist effects at muscarinic M2 and M4 receptors and antagonist effects at muscarinic M1, M3 and M5 receptors. PTAC inhibited conditioned avoidance responding, dopamine receptor agonist-induced behavior and D-amphetamine-induced FOS protein M5 expression in the nucleus accumbens without inducing catalepsy, tremor or salivation at pharmacologically relevant doses. The effect of PTAC on conditioned avoidance responding and dopamine receptor agonist-induced behavior was antagonized by the acetylcholine receptor antagonist scopolamine. The compound selectively inhibited dopamine cell firing (acute administration) as well as the number of spontaneously active dopamine cells (chronic administration) in the limbic ventral tegmental area (A10) relative to the non-limbic substantia nigra, pars compacta (A9). The results demonstrate that PTAC exhibits functional dopamine receptor antagonism despite its lack of affinity for the dopamine receptors and indicate that muscarinic receptor partial agonists may be an important new approach in the medical treatment of schizophrenia.

Animals↗

PubMed1998

1,2,5-Thiadiazole analogues of aceclidine as potent m1 muscarinic agonists.

The acetyl group of the muscarinic agonist aceclidine 4 was replaced by various 1,2,5-thiadiazoles to provide a new series of potent m1 muscarinic agonists 17 and 18. Optimal m1 muscarinic agonist potency was achieved when the 1,2,5-thiadiazole substituent was either a butyloxy, 17d, or butylthio, 18d, group. Although 1,2,5-oxadiazole 37 and pyrazine 39 are iso-pi-electronic with 1,2,5-thiadiazole 17d, both analogues were substantially less active than 17d. Compounds with high muscarinic affinity and/or m1 muscarinic agonist efficacy were also obtained when the 3-oxyquinuclidine moiety of 17d or 18c was replaced by ethanolamines, hydroxypyrrolidines, hydroxyazetidine, hydroxyisotropanes, or hydroxyazanorbornanes. The structure-activity data support the participation of the oxygen or sulfur atom in the substituent on the 1,2,5-thiadiazole in the activation of the m1 receptor. Several of these new 1,2,5-thiadiazoles have m1 agonist efficacy, potency, and selectivity comparable to those of xanomeline 2 in the muscarinic tests investigated.

Animals↗

PubMed1998

Conformationally constrained analogues of the muscarinic agonist 3-(4-(methylthio)-1,2,5-thiadiazol-3-yl)-1,2,5,6-tetrahydro-1-methylpyr idine. Synthesis, receptor affinity, and antinociceptive activity.

Conformationally constrained analogues of the potent muscarinic agonist 3-(4-methylthio)-1,2,5-thiadiazol-3-yl)-1,2,5,6-tetrahydro-1-methy lpyridine (methylthio-TZTP, 17) were designed and synthesized with the aim of (a) improving the antinociceptive selectivity over salivation and tremor and (b) predicting the active conformation of 17 with respect to the dihedral angle C4-C3-C3'-N2'. Using MOPAC 6.0 tricyclic analogues (7, 15, 16) with C4-C3-C3'-N2' dihedral angles close to 180 degrees and a rotation hindered analogue (9) with a C4-C3-C3'-N2' dihedral angle close to 274 degrees were designed, as these conformations had previously been suggested as being the active conformations. The analogues were tested for central muscarinic receptor binding affinity, for their antinociceptive activity in the mouse grid shock test, and, in the same assay, for their ability to induce tremor and salivation. The data showed that the tricyclic analogues (7, 15, 16) were equipotent with 17 as analgesics, but with no improved side effect profiles. The rotation-hindered analogue 9 had neither muscarinic receptor binding affinity nor antinociceptive activity. These results suggest that the active conformation of 17 has a C3-C4-C3'-N2' dihedral angle close to 180 degrees.

Analgesics↗

PubMed1998

Discriminative stimulus functions of CNS sedative drugs assessed by drug versus drug discrimination procedures in gerbils.

This study is concerned with dissecting out differences in the discriminative stimulus attributes between drugs from broader pharmacological categories such as sedative/hypnotics where generalization tests often indicate shared stimulus effects. To this end, the discriminative stimulus effects of three to five doses of either chlordiazepoxide (CDP), chlormethiazole (CMZ), ethanol (ETOH), and pentobarbital (P-barb) were studied with gerbils in a two-choice, T-maze task. When the discrimination was based upon the presence versus the absence of drug administration, speed of acquiring the discrimination increased dose-dependently for all four drugs with log of sessions to criterion being a linear function of log dose. The slopes of all four lines were similar. The acquisition of a discrimination based on different doses of the training drug was then examined. A two-to-one ratio of high to low doses was used. Discriminative control developed with CMZ, ETOH, and P-barb, but not with CDP. The side of the T-maze that correlated with the lower training dose was always selected in tests with saline. Gerbils were then trained to discriminate between two drugs using at least two different dose combinations. The CDP versus CMZ, CDP versus ETOH, CMZ versus P-barb, CMZ versus ETOH discriminations were acquired. The CDP versus P-barb discrimination was obtained across doses only after an additional training procedure was instituted such that the P-barb dose was incremented gradually from low to higher doses during discrimination training; the CDP training doses were 20 and 30 mg/kg in two different groups of gerbils, respectively and the dose of P-barb was incremented by 2.5 mg/kg until the final dose of 20 mg/kg was reached with the barbiturate. Thus, although often shown to share similar stimulus effects, members of the broad pharmacological class of CNS sedatives/hypnotics nonetheless were shown to be discriminable from one another. Non-drug tests (vehicle) were used to assess stimulus control between pairs of drugs, equal control being implicated when responding was evenly distributed across the two training conditions.

Animals↗

PubMed1998

Reinforcing effects of nicotinic compounds: intravenous self-administration in drug-naive mice.

The nicotinic compounds (-)-cytisine, (-)-lobeline, (+/-)-epibatidine, (S)-3methyl-5-(1-methyl-2-pyrrolidinyl)isoaxzole (ABT-418), (-)-nicotine, and cocaine were compared in an acute self-administration model using drug-naive mice that could self-administer intravenous infusions contingent on nose poking (fixed ratio 1 with no time out). Although the nose pokes of yoked control mice were unaffected by unit dose, inverted U-shaped unit dose response curves were seen with cocaine (up to 0.26 mg/kg/infusion), nicotine (up to 0.175 mg/kg/infusion), cytisine (up to 0.125 mg/kg/infusion), and lobeline (up to 1.25 mg/kg/infusion) in mice receiving infusions contingent upon nose poke responses. Epibatidine (up to 1.25 microg/kg/infusion) and ABT-418 (up to 0.125 mg/kg/infusion) failed to exhibit inverted U-shaped unit dose response curves. The present studies demonstrate that cytisine and lobeline, but not ABT-418 or epibatidine, were self-administered by drug-naive mice in a manner similar to cocaine and nicotine. These findings are discussed in terms of potency and selectivity at the alpha4beta2 nicotinic acetylcholine receptor subunit combination.

Animals↗

PubMed1998

3-(5-Alkylamino-4-isoxazolyl)-1,2,5,6-tetrahydropyridines: a novel class of central nicotinic receptor ligands.

A novel class of central nicotinic acetylcholine receptor ligands, 3-(5-alkylamino-4-isoxazolyl)-1,2,5,6-tetrahydropyridine 4a-f, was synthesized. Several of the compounds showed high affinity for central nicotinic receptors (4c: IC50 = 50 nM), with more than a 100-fold selectivity for nicotinic over muscarinic receptors. The compounds showed up to a 10-fold selectivity for the central nicotinic subtype combination alpha 4 beta 2 (4c: IC50 = 4.6 nM), as compared to the major ganglionic subtype composed of alpha 3 containing subunits (4c: IC50 = 48 nM). The compounds were further evaluated in a dopamine release assay in vitro, and in a drug discrimination assay in vivo. Compound 4a is an effective nicotinic agonist with a potency 50-100 times lower than nicotine. Extending the alkylamino chain beyond one, compound (4b-f), changed the pharmacological profile of the compounds in an antagonistic direction.

Animals↗

PubMed1997

Muscarinic analgesics with potent and selective effects on the gastrointestinal tract: potential application for the treatment of irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a pathopysiolocal condition characterized by abnormal bowel habits that are frequently accompanied by abdominal pain. Current therapy based on reducing high-amplitude GI contractions with nonselective muscarinic antagonists is limited in efficacy due to typical muscarinic side effects and provides no pain relief. We have previously found potent antinociceptive agents acting through muscarinic receptors. In the present work, new 1,2,5-thiadiazole-based structures with muscarinic activity have been evaluated both for activity as analgesics in the mouse withing assay and for activity in normalizing spontaneous cluster contractions in ferret jejunum as a model of IBS in humans. (5R,6R)-exo-6-[4-[(4,4,4-Trifluorobutyl)thio]-1,2,5-thiadiazol+ ++-3-yl] -1-azabicyclo[3.2.1]octane (35, LY316108/NNC11-2192) was found to offer an exceptional profile combining analgesic potency in mouse writhing (ED50 = 0.1 mg/kg) along with potency for normalization of GI motility (ED50 = 0.17 mg/kg). This combination of GI and analgesic potency suggests 35 as an excellent candidate for evaluation as a potential treatment of IBS.

Analgesics, Non-Narcotic↗

PubMed1997

NNC-19-1228 and NNC 22-0031, novel neuroleptics with a "mesolimbic-selective" behavioral profile.

NNC 19-1228 [1-(3(6-methylenedioxyphenylcarbamoyloxy) propyl)-4-(6-fluoro-1,2-benzisoxazol-3-yl) piperidine] and NNC 22-0031 [4-(6-fluoro-1,2-benzisoxazol-3-yl) -1-(3-(3,4-methylenedioxyphenylcarbamoyloxy) propyl)piperidine] are newly developed compounds with an in vitro pharmacologic profile similar to that of clozapine, i.e., mixed dopamine (DA), 5-hydroxytryptamine (5-HT)2 and alpha 1-adrenergic antagonist action. In pharmacological experiments in mice, the compounds inhibited DA D2 receptor binding in vivo at doses that produced only moderate antagonism of methylphenidate (MPD)-induced stereotyped gnawing. However, the compounds were markedly more potent in blocking MPD-induced motility, a model which showed a high degree of sensitivity to alpha 1-adrenergic antagonism, but not 5-HT2 antagonism. In rats, the NNC-compounds blocked conditioned avoidance responding and attenuated the discriminative stimulus effects of amphetamine, but failed to induce catalepsy. These results are discussed in terms of adrenergic, serotonergic and dopaminergic interactions which suggest that the NNC compounds may act as DA antagonists with mesolimbic selectivity, and thus may have efficacy as antipsychotics without coincident extrapyramidal side effects.

Amphetamine↗