Synthesis and preliminary CNS depressant activity evaluation of new 3-[(3-substituted-5-methyl-4-thiazolidinon-2-ylidene)hydrazono]-1H-2- indolinones and 3-[(2-thioxo-3-substituted-4,5-imidazolidinedion-1-yl) imino]-1H-2-indolinones

A series of (+/-) 3-[(3-substituted-5-methyl-4-thiazolidinon-2- ylidene)hydrazono]-1H-2-indolinones (2a-h) and 3-[(2-thioxo-3-substituted-4,5-imidazolidinedion-1-yl)imino] -1H-2-indolinones (3a-g) were synthesized by the cyclization of 3-(4-substituted-thiosemicarbazono)-1H-2-indolinones (1a-h) with ethyl 2-bromopropionate in anydrous ethanolic medium and oxalyl chloride in anhydrous diethyl ether, respectively. The structures of 2 and 3 were confirmed by analytical and spectral data (IR, 1H NMR, 13C NMR, and EIMS). The configuration of 3 was assigned on the basis of 1H NMR and 13C NMR data. 2c, 2d, 2g, 2h, and 3a-g were evaluated for anticonvulsant activity against maximal electroshock (MES) and subcutaneous pentylenetetrazol (ScMet) induced seizures. Among the compounds tested, only 2d exhibited some activity in anticonvulsant identification (Phase I) trials in mice. 2a, 2b, 2d, 2g, 2h, and 3a-g were additionally tested for potentiating effects on pentobarbital induced hypnosis in mice. All of the test compounds increased the sleeping time of pentobarbital significantly (p < 0.05) and the most potent compound was found to be 3a.     

Synthesis and in vitro characterization of N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8- tetrahydronaphthalen-1-yl]methanesulfonamide and its enantiomers: a novel selective alpha 1A receptor agonist

The existence of multiple subtypes of the alpha 1 adrenergic receptor has been demonstrated both pharmacologically and by molecular biological cloning techniques. The development of subtype selective antagonists has been the focus of much research within the pharmaceutical industry, and clinical evidence now exists that alpha-1A selective antagonists will have utility in the treatment of benign prostatic hyperplasia. However, highly subtype selective agonists are not known. Herein we report the synthesis and pharmacological characterization of N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8- tetrahydronaphthalen-1-yl]methanesulfonamide and its enantiomers, a highly potent full agonist with excellent selectivity for the alpha 1A receptor subtype.     

YM022 [(R)-1-[2,3-dihydro-1-(2''-methylphenacyl)-2-oxo-5-phenyl-1H-1,4- benzodiazepin-3-yl]-3-(3-methylphenyl)urea]: an irreversible cholecystokinin type-B receptor antagonist

It is controversial whether osteopontin (OP) is expressed in glomeruli and involved in glomerular diseases. We examined whether the OP expression is present at gene and protein levels in cultured rat mesangial cells (MCs). Northern blotting revealed a 1.7 kb OP-mRNA expression in MCs. Fetal calf serum (FCS) and TNF-alpha increased OP gene expression in serum-starved MCs by 2.7- and 1.8-fold over 24- and 12-hour periods, respectively. PDGF, IL-1beta, and TGF-beta had little effect on OP gene expression. Western blotting detected the OP protein expression (69 kDa). FCS and TNF-alpha increased OP protein expression in serum-starved MCs over 48- and 24-hour periods, respectively. The present study clearly demonstrated the expression of OP gene and protein in cultured rat MCs. Increased OP production under serum or TNF-alpha stimulation suggests that intraglomerular OP may contribute to the development of glomerular diseases.     

Development of orally active oxytocin antagonists: studies on 1-(1-[4-[1-(2-methyl-1-oxidopyridin-3-ylmethyl)piperidin-4-yloxy]-2- methoxybenzoyl]piperidin-4-yl)-1,4-dihydrobenz[d][1,3]oxazin-2-one (L-372,662) and related pyridines

The previously reported oxytocin antagonist L-371,257 (2) has been modified at its acetylpiperidine terminus to incorporate various pyridine N-oxide groups. This modification has led to the identification of compounds with improved pharmacokinetics and excellent oral bioavailability. The pyridine N-oxide series is exemplified by L-372,662 (30), which possessed good potency in vitro (Ki = 4.1 nM, cloned human oxytocin receptor) and in vivo (intravenous AD50 = 0.71 mg/kg in the rat), excellent oral bioavailability (90% in the rat, 96% in the dog), good aqueous solubility (>8.5 mg/mL at pH 5.2) which should facilitate formulation for iv administration, and excellent selectivity against the human arginine vasopressin receptors. Incorporation of a 5-fluoro substituent on the central benzoyl ring of this class of oxytocin antagonists enhanced in vitro and in vivo potency but was detrimental to the pharmacokinetic profiles of these compounds. Although lipophilic substitution around the pyridine ring of compound 30 gave higher affinity in vitro, such substituents were a metabolic liability and caused shortfalls in vivo. Two approaches to prevent this metabolism, addition of a cyclic constraint and incorporation of trifluoromethyl groups, were examined. The former approach was ineffective because of metabolic hydroxylation on the constrained ring system, whereas the latter showed improvement in plasma pharmacokinetics in some cases.     

(+)-4-[2-[4-(8-Chloro-3,10-dibromo-6,11-dihydro-5H-benzo[5, 6]cyclohepta[1,2-b]- pyridin-11(R)-yl)-1-piperidinyl]-2-oxo-ethyl]-1-piperidinecarboxamid e (SCH-66336): a very potent farnesyl protein transferase inhibitor as a novel antitumor agent

We have previously shown that appropriate modification of the benzocycloheptapyridine tricyclic ring system can provide potent farnesyl protein transferase (FPT) inhibitors with good cellular activity. Our laboratories have also established that incorporation of either pyridinylacetyl N-oxide or 4-N-carboxamidopiperidinylacetyl moieties results in pharmacokinetically stable inhibitors that are orally efficacious in nude mice. We now demonstrate that further elaboration of the tricyclic ring system by introducing a bromine atom at the 7- or the 10-position of the 3-bromo-8-chlorotricyclic ring system provides compounds that have superior potency and selectivity in FPT inhibition. These compounds have good serum levels and half-lives when given orally to rodents and primates. In vitro and in vivo evaluation of a panel of these inhibitors has led to identification of 15 (SCH 66336) as a highly potent (IC50 = 1.9 nM) antitumor agent that is currently undergoing human clinical trials.     

Synthesis and pharmacological evaluation of 1-methyl-5-[substituted-4 (3H)-oxo-1,2,3-benzotriazin-3-yl]-1H-pyrazole-4-acetic acid derivatives

Several new 1-methyl-5-[substituted-4-oxo-1,2,3-benzotriazin-3-yl] -1H-pyrazole-4-acetic acids and their ethyl ester derivatives were prepared. The compounds were tested for analgesic and antiinflammatory activities, acute toxicity, ulcerogenic effect, and as in vitro inhibitors of 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), since it is claimed that the inhibition of such an enzyme predicts in vivo antiinflammatory activity. Some compounds were more active than phenylbutazone in the phenylbenzoquinone and acetic acid peritonitis tests, and equiactive to the same drug in the carrageenin paw edema test. All the compounds inhibited the 3 alpha-HSD, but no correlation was observed with the paw edema inhibition values. The compounds proved to possess marginal or no ulcerogenic effect, as well as low systemic toxicity.     

Serotonin 5-HT4 receptor agonistic activity of the optical isomers of (+/-)-4-amino-N-[2-(1-azabicyclo[3.3.0]octan-5-yl)ethyl]-5-chloro-2,3- dihydro-2-methylbenzo[b]furan-7-carboxamide

OBJECTIVE: To compare the influence of incongruent (asymmetric) follicular development on treatment outcome in IVF-ET and GIFT cycles. DESIGN: A retrospective comparative study. SETTING: Tertiary referral center for infertility. PATIENT(S): Five hundred forty-three consecutive assisted reproduction cycles (428 IVF-ET and 115 GIFT) in 422 infertile patients. INTERVENTION(S): Controlled ovarian hyperstimulation (COH) and IVF-ET or GIFT. MAIN OUTCOME MEASURE(S): The incongruity ratio as a parameter of the asymmetry in follicular development and pregnancy rate (PR). RESULT(S): For GIFT cycles, the PRs were 37.8% and 15.7% in cycles with congruent and incongruent follicular development, respectively. However, for IVF-ET cycles, the PR was not affected by incongruent follicular development: 28.2% and 29.0%, respectively. An inverse relationship was observed between the degree of incongruity and the estimated probability of pregnancy in GIFT cycles but not in IVF-ET cycles. Neither the side of the dominant ovary nor the degree of incongruity were consistent in consecutive cycles. CONCLUSION(S): Incongruent follicular development during COH has a significantly negative influence on the outcome of GIFT cycles but not on the outcome of IVF-ET cycles. The reason for this difference is not clear. We recommend considering IVF-ET instead of GIFT if incongruent follicular development occurs.     

N-[2-(1-azabicyclo[3.3.0]octan-5-yl)ethyl]-2-nitroaniline, a potent muscarinic agonist

The muscarine receptor agonist SK-946, an aniline derivative with a characteristic bicyclo amine, was found. We describe a new synthetic method for 1-azabicyclo[3.3.0]octane and describe the biological activity of SK-946.     

Preparation of 8-[3-(4-fluorobenzoyl)-propyl]-1-(4-[123I] iodobenzoyl)-1,3,8-triazaspiro[4,5]decan-4-one: a novel selective serotonin 5-HT2 receptor agent

OBJECTIVE: to evaluate the effectiveness of a reduced-frequency prenatal visit schedule by comparing perinatal outcomes, anxiety and maternal satisfaction with prenatal care. METHODS: pregnancy outcomes of infant and maternal morbidity and mortality, anxiety and satisfaction for 81 women receiving prenatal care at a free-standing birthing center according to either an alternative prenatal care visit schedule (APCVS) (n = 43) or the traditional prenatal care visit schedule (TPCVS) (n = 38) were examined in this prospective randomized study. Upon entry into prenatal care, all women were of low obstetrical risk status. RESULTS: major findings revealed no significant differences in selected perinatal outcomes between the two study groups. Women in the APCVS group reported significantly higher levels of satisfaction than women in the TPCVS group on both the satisfaction with provider subscale (F = 5.74, P = .02) and the satisfaction with the prenatal care system subscale (F = 2.01, P = .04). There were no statistically significant differences found in anxiety scores between women in the two study groups. CONCLUSIONS: low-risk women who followed the reduced-frequency visit schedule experienced no difference in perinatal outcomes or anxiety. Women in the reduced-frequency (APCVS) group reported an increased level of satisfaction with both provider and the prenatal care system.     

The selective 5-HT1B receptor inverse agonist 1'-methyl-5-[[2'-methyl-4'-(5-methyl-1,2, 4-oxadiazol-3-yl)biphenyl-4-yl]carbonyl]-2,3,6,7-tetrahydro- spiro[furo[2,3-f]indole-3,4'-piperidine] (SB-224289) potently blocks terminal 5-HT autoreceptor function both in vitro and in vivo

5-HT1 receptors are members of the G-protein-coupled receptor superfamily and are negatively linked to adenylyl cyclase activity. The human 5-HT1B and 5-HT1D receptors (previously known as 5-HT1Dbeta and 5-HT1Dalpha, respectively), although encoded by two distinct genes, are structurally very similar. Pharmacologically, these two receptors have been differentiated using nonselective chemical tools such as ketanserin and ritanserin, but the absence of truly selective agents has meant that the precise function of the 5-HT1B and 5-HT1D receptors has not been defined. In this paper we describe how, using computational chemistry models as a guide, the nonselective 5-HT1B/5-HT1D receptor antagonist 4 was structurally modified to produce the selective 5-HT1B receptor inverse agonist 5, 1'-methyl-5-[[2'-methyl-4'-(5-methyl-1,2, 4-oxadiazol-3-yl)biphenyl-4-yl]carbonyl]-2,3,6, 7-tetrahydrospiro[furo[2,3-f]indole-3,4'-piperidine] (SB-224289). This compound is a potent antagonist of terminal 5-HT autoreceptor function both in vitro and in vivo.     

Heteroaromatic analogs of 1-[2-(diphenylmethoxy)ethyl]- and 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazines (GBR 12935 and GBR 12909) as high-affinity dopamine reuptake inhibitors

A new series of heteroaromatic GBR 12935 [1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)-piperazine] (I) and GBR 12909 [1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine] (2) analogs was synthesized and evaluated as dopamine transporter (DAT) ligands. Analogs 5-16, in which the benzene ring in the phenylpropyl side chain of the GBR molecule had been replaced with a thiophene, furan, or pyridine ring, exhibited high affinity and selectivity for the DAT vs serotonin transporter (SERT) and stimulated locomotor activity in rats in a manner similar to the parent compound 2. In cocaine and food self-administration studies in rhesus monkeys, both thiophene-containing (6 and 8) and pyridine-containing (14 and 16) derivatives displayed potency comparable to 2 in decreasing the cocaine-maintained responding at the doses tested (0.8, 1.7, and 3 mg/kg). However, these compounds did not produce the degree of separation between food- and cocaine-maintained responding that was seen with 2. Among the bicyclic fused-ring congeners 17-38, the indole-containing analog of 2, 22, showed the greatest affinity for binding to the DAT, with IC50 = 0.7 nM, whereas the corresponding indole-containing derivative of 1, 21, displayed the highest selectivity (over 600-fold) at this site vs the SERT site.     

N-[2-[4-(4-Chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide: a potent and selective dopamine D4 ligand

A series of new 1-aryl-4-alkylpiperazines containing a terminal benzamide fragment or a tetralin-1-yl nucleus on the alkyl chain were synthesized and tested for binding at cloned human dopamine D4 and D2 receptor subtypes. A SAFIR (structure-affinity relationship) study on this series is herein discussed. The most relevant D4 receptor affinities were displayed by N-[omega-[4-arylpiperazin-1-yl]alkyl]-methoxybenzamides (compounds 5, 16-20), their IC50 values ranging between 0.057 and 7.8 nM. Among these, N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide (17) emerged since it exhibited very high affinity for dopamine D4 receptor (IC50 = 0.057 nM) with selectivity of >10 000 for the D4 versus the D2 receptor; compound 17 was also selective versus serotonin 5-HT1A and adrenergic alpha1 receptors.     

7-[3-(1-piperidinyl)propoxy]chromenones as potential atypical antipsychotics. 2. Pharmacological profile of 7-[3-[4-(6-fluoro-1, 2-benzisoxazol-3-yl)-piperidin-1-yl]propoxy]-3-(hydroxymeth yl)chromen -4-one (abaperidone, FI-8602)

A series of novel 7-[3-(1-piperidinyl)propoxy]chromenones was synthesized and tested as potential antipsychotics in several in vitro and in vivo assays. The compounds possessed good affinity for D2 receptors, together with a greater affinity for 5-HT2 receptors, a profile which has been proposed as a model for atypical antipsychotics. Several agents also displayed a high potency in the climbing mice assay on oral administration, suggesting a potent antipsychotic effect as compared to reference standards. Compound 23 was selected for further pharmacological evaluation. Induction of catalepsy and inhibition of stereotypies weaker than standards, along with a lower increase in serum prolactin levels, were indicative of a potential atypical profile for this compound. From these results, 7-[3-[4-(6-fluoro-1, 2-benzisoxazol-3-yl)piperidin-1-yl]propoxy]-3-(hydroxymethyl )chromen- 4-one (23, abaperidone) has been proposed for clinical evaluation in humans as a potential atypical antipsychotic.     

S 18126 ([2-[4-(2,3-dihydrobenzo[1,4]dioxin-6-yl)piperazin-1-yl methyl]indan-2-yl]), a potent, selective and competitive antagonist at dopamine D4 receptors: an in vitro and in vivo comparison with L 745,870 (3-(4-[4-chlorophenyl]piperazin-1-yl)methyl-1H-pyrrolo[2, 3b]pyridine) and raclopride

The novel benzoindane S 18126 possessed > 100-fold higher affinity at cloned, human (h) D4 (Ki = 2.4 nM) vs. hD2 (738 nM), hD3 (2840 nM), hD1 (> 3000 nM) and hD5 (> 3000 nM) receptors and about 50 other sites, except sigma1 receptors (1.6 nM). L 745,870 similarly showed selectivity for hD4 (2.5 nM) vs. hD2 (905 nM) and hD3 (> 3000 nM) receptors. In contrast, raclopride displayed low affinity at hD4 (> 3000 nM) vs. hD2 (1.1 nM) and hD3 receptors (1.4 nM). Stimulation of [35S]-GTPgammaS binding at hD4 receptors by dopamine (DA) was blocked by S 18126 and L 745,870 with Kb values of 2.2 and 1.0 nM, respectively, whereas raclopride (> 1000 nM) was inactive. In contrast, raclopride inhibited stimulation of [35S]-GTPgammaS binding at hD2 sites by DA with a Kb of 1.4 nM, whereas S 18126 (> 1000 nM) and L 745,870 (> 1000 nM) were inactive. As concerns presynaptic dopaminergic receptors, raclopride (0.01-0.05 mg/kg s.c. ) markedly enhanced DA synthesis in mesocortical, mesolimbic and nigrostriatal dopaminergic pathways. In contrast, even high doses (2. 5-40.0 mg/kg s.c.) of S 18126 and L 745,870 were only weakly active. Similarly, raclopride (0.016 mg/kg i.v.) abolished inhibition of the firing rate of ventrotegmental dopaminergic neurons by apomorphine, whereas even high doses (0.5 mg/kg i.v.) of S 18126 and L 745,870 were only weakly active. As regards postsynaptic dopaminergic receptors, raclopride potently (0.01-0.3 mg/kg s.c.) reduced rotation elicited by quinpirole in rats with unilateral lesions of the substantia nigra, antagonized induction of hypothermia by PD 128, 907, blocked amphetamine-induced hyperlocomotion and was effective in six further models of potential antipsychotic activity. In contrast, S 18126 and L 745,870 were only weakly active in these models (5.0-> 40.0 mg/kg s.c.). In six models of extrapyramidal and motor symptoms, such as induction of catalepsy, raclopride was likewise potently active (0.01-2.0 mg/kg s.c.) whereas S 18126 and L 745,870 were only weakly active (10.0-80.0 mg/kg s.c.). In freely moving rats, raclopride (0.16 mg/kg s.c.) increased levels of DA by + 55% in dialysates of the frontal cortex. However, it also increased levels of DA in the accumbens and striatum by 70% and 75%, respectively. In contrast to raclopride, at a dose of 0.16 mg/kg s.c. , neither S 18126 nor L 745,870 modified frontal cortex levels of DA. However, at a high dose (40.0 mg/kg s.c.), S 18126 increased dialysate levels of DA (+ 85%) and noradrenaline (+ 100%), but not serotonin (+ 10%), in frontal cortex without affecting DA levels in accumbens (+ 10%) and striatum (+ 10%). In conclusion, S 18126 and L 745,870 behave as potent and selective antagonists of cloned, hD4 vs. other dopaminergic receptor types in vitro. However, their in vivo effects at high doses probably reflect residual antagonist actions at D2 (or D3) receptors. Selective blockade of D4 receptors was thus associated neither with a modification of dopaminergic transmission nor with antipsychotic (antiproductive) or extrapyramidal properties. The functional effects of selective D4 receptor blockade remain to be established.     

Effects of R(-)-1-(benzo[b]thiophen-5-yl)-2-[2-N,N-diethylamino)ethoxy]ethan ol hydrochloride (T-588), a novel cognitive enhancer, on noradrenaline release in rat cerebral cortical slices

We investigated the effects of R(-)-1-(benzo[b]thiophen-5-yl)-2-[2-(N,N-diethylamino)ethoxy]ethan ol hydrochloride (T-588), a novel cognitive enhancer, on noradrenaline (NA) release from rat cerebral cortical slices in vitro. Addition of T-588 in an assay mixture stimulated [3H]NA release from prelabeled slices in the presence or absence of extracellular CaCl2, and in the presence of the Ca2+/calmodulin antagonists N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and trifluoperazine. T-588 stimulated NA release with a time lag of about 1 min, and the high level of release was maintained for at least 10 min, whereas maximal KCl-evoked NA release was observed within 1 min after the addition of KCl, and the effect declined subsequently. The effect of T-588 was reversible (pretreatment with T-588 showed no effect on NA release after two washes by centrifugation). We also compared the effects of T-588 and N-ethylmaleimide (NEM), a sulfhydryl alkylating agent known to stimulate neurotransmitter release in several types of cells. The addition of NEM stimulated NA release irreversibly from the slices in a Ca2+-independent manner, and the effect of NEM, but not that of T-588, was inhibited by the simultaneous addition of dithiothreitol, a sulfhydryl group reducing agent. The addition of T-588, which stimulated NA release by itself, inhibited the NA release by 0.6 mM NEM, although the effect of T-588 was additive in the presence of 0.2 mM NEM. These findings suggest that T-588 stimulates NA release from rat cerebral cortical slices in a Ca2+- and calmodulin-independent manner, possibly via an NEM-sensitive factor(s), although the mechanism of the effects of T-588 seems to be different from that of NEM.     

1-[2,3,5-三氮唑偶氮]-5-甲基-2-苯酚的合成及其与钴的显色反应

合成了 1 [2 ,3 ,5 三氮唑偶氮 ] 5 甲基 2 苯酚 (简称TZAMP) ,并研究了其与钴的显色反应。结果表明 :在 pH5～ 6的邻苯二甲酸氢钾 氢氧化钠缓冲介质中 ,该试剂与钴形成络合比为 1∶1的红色络合物 ,λmax=5 90 6nm ,表观摩尔吸光系数ε=2 5 8× 10 4 ,钴量在 0～ 1 6mg/L范围内遵守比尔定律。     

Study on major metabolites of 3H-1,2-dihydro-2-(4-methylphenylamino)-methyl-1-pyrrolizinone in rabbits]

The metabolites of a 750 mg oral dose of Z-47 [3H-1, 2-dihydro-2-(4-methylphenylamino) methyl-1-pyrrolizinone], a new anti-inflammatory and analgesic agent, in rabbit urine were separated and detected with high performance liquid chromatographic method. On basis of the chromatographic behavior of Z-47 metabolites and biotransformation pathways of drugs with partial structure of Z-47, the carboxylic derivative of Z-47 [4-(3H-1, 2-dihydro-1-pyrrolizinone-2-methylamino) benzoic acid] was proposed as a potential metabolite so that the compound was synthesized. The authentic substance was then compared with one of the metabolites by the chromatographic retention time and the ratio of their UV-absorbances at two wavelengths. The enzyme-hydrolyzed product of another metabolite was also analysed. It was consequently confirmed that the carboxylic derivative of Z-47 and its acyl beta-D-glucuronide are major metabolits of Z-47 in rabbits.     

Anandamide- and delta9-tetrahydrocannabinol-evoked arachidonic acid mobilization and blockade by SR141716A [N-(Piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4 -methyl-1H-pyrazole-3-carboximide hydrochloride]

The purpose of this study was to investigate whether anandamide induces cannabimimetic responses, mainly mobilization of arachidonic acid, in primary cultures of rat brain cortical astrocytes. Confluent monolayer cultures of astrocytes, prelabeled with [3H]arachidonic acid, were incubated with anandamide or delta9-tetrahydrocannabinol (delta9-THC) in the presence or absence of thimerosal, a fatty acid acyl CoA transferase inhibitor and phenylmethylsulfonyl fluoride, an amidohydrolase inhibitor. Anandamide and delta9-THC induced a time- and concentration-dependent release of arachidonic acid in the presence, but not in the absence, of thimerosal. Anandamide- and delta9-THC-stimulated arachidonic acid release was pertussis toxin-sensitive, indicating a receptor/G-protein involvement. A novel and selective cannabinoid receptor antagonist, SR141716A [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4- methyl-1H-pyrazole-3-carboximide hydrochloride], blocked the arachidonic acid release, suggesting a cannabinoid receptor-mediated pathway. In astrocytes, the magnitude of anandamide-induced arachidonic acid release was equal to that released by equimolar concentrations of delta9-THC. Furthermore, direct assay of amidohydrolase activity indicated that degradation of anandamide into arachidonic acid and ethanolamine was negligible in cortical astrocytes. Our results suggest that anandamide stimulates receptor-mediated release of arachidonic acid, and the receptor may be the cannabinoid receptor. Astrocytes, containing a cannabinoid receptor and lower or negligible amidohydrolase activity, may be an important brain cell model in which to study the cannabimimetic effects of anandamide at a cellular and molecular level.