Synthesis and microbial evaluation of novel N(1)-Arilidene-N(2)-t(3)-methyl-r(2),c(6)-diaryl-piperidin-4-one azine derivatives

Some novel N(1)-arylidene-N(2)-t(3)-methyl-r(2),c(6)-diarylpiperidin-4-one azine derivatives were synthesized and their antibacterial activity against Streptococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and antifungal activity against Candida-6, Candida-51, Aspergillus niger, and Aspergillus flavus evaluated.     

Cloning,pharmacological characterisation and tissue distribution of a novel 5-HT<Subscript>4</Subscript> receptor splice variant, 5-HT<Subscript>4(i)</Subscript>

5-HT₄ receptor pre-mRNA is alternatively spliced in human (h) tissue to produce several splice variants, called 5-HT_4(a) to 5-HT_4(h) and 5-HT_4(n). Polymerase chain reaction (PCR) with primers designed to amplify both 5-HT_4(a) and 5-HT_4(b) amplified three additional bands in different tissues, two representing different mRNA species both encoding 5-HT_4(g) and one representing mRNA for a novel splice variant named 5-HT_4(i), cloned from testis and pancreas respectively. Primary and nested PCR detected both 5-HT_4(g) and 5-HT_4(i) in multiple tissues. Whereas 5-HT_4(i), was found in all cardiovascular tissues analysed, 5-HT_4(g) was mainly present in atria. However, quantitative RT-PCR indicated 5-HT_4(g) expression also in cardiac ventricle. The pharmacological profiles and ability to activate adenylyl cyclase (AC) were compared between four recombinant h5-HT₄ splice variants (a, b, g and i) expressed transiently and stably in HEK293 cells. Displacement of [³H]GR113808 with ten ligands revealed identical pharmacological profiles (affinity rank order: GR125487, SB207710, GR113808>SB203186>serotonin, cisapride, tropisetron>renzapride, 5-MeOT>5-CT). In transiently transfected HEK293 cells cisapride was a partial agonist compared to serotonin at 5-HT_4(b), 5-HT_4(g) and 5-HT_4(i) receptors. In membranes from HEK293 cells stably expressing 5-HT_4(g) (3,000 fmol/mg protein) or 5-HT_4(i) (500 fmol/mg protein), serotonin and 5-MeOT were full agonists while cisapride was full agonist at 5-HT_4(g) and partial agonist at 5-HT_4(i), probably due to different receptor expression levels. At both 5-HT_4(g) and 5-HT_4(i), the behaviour of 5-HT₄ receptor antagonists was dependent on receptor level. At high receptor levels, tropisetron and SB207710 and to a variable extent SB203186 and GR113808 displayed some partial agonist activity, whereas GR125487 and SB207266 reduced the AC activity below basal, indicating both receptors to be constitutively active. We conclude that the novel 5-HT_4(i) receptor splice variant is pharmacologically indistinguishable from other 5-HT₄ splice variants and that the 5-HT_4(i) C-terminal tail does not influence coupling to AC.     

Hypotensive effect of anandamide through the activation of CB<Subscript>1</Subscript> and VR<Subscript>1</Subscript> spinal receptors in urethane-anesthetized rats

This study examined the effect of intrathecal (i.t.) injection of the endocannabinoid anandamide in urethane-anesthetized rats. The tip of the i.t. cannula was positioned at the T₁₂–L₁ level of the spinal cord. Either anandamide or its metabolically stable analogue methanandamide (25 to 100 nmol) produced dose-dependent decreases in the blood pressure that persisted at least for up to 30 min. The hypotensive responses to 100 nmol anandamide and to 100 nmol methanandamide were –17.7±1.6 mmHg (n=5) and –17.9±2.0 mmHg (n=4), respectively. Hypotensive effects were also obtained with the CB₁ cannabinoid receptor agonist WIN 55212-2 (20 nmol; i.t.) as well as with the vanilloid VR₁ receptor agonist capsaicin (3 nmol; i.t.). Nicotinic ganglionic blockade with hexamethonium bromide [10 mg/kg; intravenous(i.v.)] abolished the responses to both anandamide and capsaicin. The i.t. administration of the CB₁ receptor antagonist, 20 nmol SR 141716A, as well as the VR₁ receptor antagonist, 20 nmol capsazepine, prevented almost completely the hypotensive responses to both anandamide and methanandamide. SR 141716A prevented the hypotension caused by WIN 55212-2 but did not modify the response to the vanilloid receptor agonist capsaicin. On the contrary, capsazepine antagonized the hypotension caused by capsaicin but failed to affect the decrease in blood pressure caused by the CB1 cannabinoid receptor agonist WIN 55212-2. These results suggest that anandamide could modulate the blood pressure through the activation of cannabinoid CB₁ receptors and vanilloid VR₁ receptors localized at the spinal cord.     

Synthesis,anti-fibrosis activity,and quantitative structure-activity relationship studies of 1,3-disubstituted-pyridin-4(1H)-one derivatives

A series of 1,3-disubstituted-pyridin-4(1H)-one derivatives were synthesized. The results of a viability assay on NIH₃T₃ cells indicated that compound 3m potently inhibited the cell viability with an IC₅₀ value of 2.0 μM. The 3D-quantitative structure-activity relationship analyses of 30 final molecules applying topomer CoMFA and AutoGPA methods gave two reasonable models with a cross-validated correlation coefficient q² of 0.662 and 0.787, respectively. The achievement herein suggested the application of 3-hydroxypyridin-4(1H)-one as a novel scaffold for the discovery of anti-fibrosis agents. In addition, the QSAR and pharmacophore models established with the activity data may provide new insights into the structure optimization of pyridin-4(1H)-one derivative with potent anti-fibrotic effects.     

苯并吡喃-4-酮衍生物的合成及其趋骨性探讨

目的 根据具有趋骨性的化合物的共同特征，设计并合成苯并吡喃-4-酮类化合物，检测它们的趋骨性。方法 以苯并吡喃-4-酮为核心，设计并合成了6个在其3位、5位、6位有酚羟基、甲氧基、羧基、酯基、甲氧羰甲氧基等基团的衍生物，用羟基磷灰石吸附实验检测其趋骨性。结果 所有合成的目标化合物的结构均经过IR，^1H—NMR和MS确认。结论 部分设计的苯并吡喃-4-酮衍生物具有比四环紊更好的趋骨性。     

Effects of activation of central nervous histamine receptors in cardiovascular regulation; studies in H<Subscript>1</Subscript> and H<Subscript>2</Subscript> receptor gene knockout mice

To elucidate the central roles of histamine receptors in cardiovascular regulatory system, systolic, mean, and diastolic blood pressures (BPs) and heart rate (HR) were examined in conscious H₁ receptor gene knockout (H₁KO) mice, H₂ receptor gene knockout (H₂KO) mice, H₁ and H₂ receptor gene double knockout (DKO) mice, and their respective control mice by the tail-cuff system. Histamine, histamine-trifluoromethyl-toluidine derivative (HTMT, an H₁ agonist), dimaprit (an H₂ agonist), and immepip (an H₃ agonist) were intrathecally administered to these KO mice and control mice. Basal BPs and HR were not different among these three KO mice and their control or wild-type mice. Intrathecal administration of histamine significantly increased BPs and decreased HR in control mice. The increases in BPs were produced by histamine in H₁KO and H₂KO mice and by HTMT and dimaprit in C57BL mice. The pressor responses by HTMT and dimaprit in C57BL mice were greater than those by histamine in H₁KO and H₂KO mice, although the same decreases in HR were induced by histamine in C57BL and H₁KO mice and by dimaprit in C57BL mice. The selective stimulation of H₃ receptors by immepip produced a consistent decrease in BPs in control mice. These results obtained with the exogenous selective agonists of three histamine receptors suggest that the pressor responses to histamine are mediated through the stimulation of both H₁ and H₂ receptors, whereas the atropine-sensitive decrease in heart rate is mainly due to H₂ receptors which activate the vagal output to the heart.     

Synthesis and antimicrobial evaluation of some novel 2-aminothiazole derivatives of 4-hydroxy-chromene-2-one

Syntheses of 2-aminothiazole derivatives of 4-hydroxy-chromene-2-one 2c-10c are reported in this paper. These compounds 2c-10c were prepared from 3-(2-bromoacetyl)-4-hydroxy-chromene-2-one 1 and corresponding thiourea derivatives 2b-10b using Hantzsch reaction. The structures of all compounds were confirmed by IR and( 1)H-NMR spectroscopy and elemental analyses. The molecules 2c-10c were evaluated for in vitro antimicrobial activity against ten bacteria and twelve fungi. All tested compounds exhibited antibacterial and antifungal activity.     

Importance of D<Subscript>1</Subscript> receptors for associative components of amphetamine-induced behavioral sensitization and conditioned activity: a study using D<Subscript>1</Subscript> receptor knockout mice

Rationale Repeated exposure to psychostimulant drugs results in conditioned activity and behavioral sensitization. Nonassociative cellular changes are necessary for behavioral sensitization, while associative processes appear to modify the sensitized response.Objective The purpose of the present study was to determine whether the absence of the D₁ receptor would disrupt associative processes modulating sensitization and conditioned activity.Methods Wild-type and D₁ receptor knockout mice (i.e., D₁-deficient mice) were injected with amphetamine (AMPH; 8 mg/kg, IP) before being placed in a previously novel test chamber (AMPH-Test group) or before being returned to the home cage (AMPH-Home group). Separate groups of mice were injected with saline (SAL) at the same time points. Distance traveled was measured 60 min each day, with the preexposure phase lasting 1 or 7 days. Sensitization was subsequently assessed after an injection of AMPH (1 mg/kg, IP), while conditioned activity was assessed after an injection of SAL.Results After a 1-day preexposure phase, wild-type and D₁-deficient mice exhibited similar patterns of sensitization and conditioned activity. After a 7-day preexposure phase, (1) D₁-deficient mice exhibited more robust context-specific sensitization than wild-type mice, (2) only D₁-deficient mice showed context-independent sensitization, and (3) only D₁-deficient mice showed conditioned activity.Conclusions Repeatedly treating D₁-deficient mice with AMPH appears to cause a general increase in responsivity. The reason for this hyper-responsivity is uncertain, but it is possible that cues from the testing environment were unable to inhibit responding (i.e., associative processes were disrupted). Alternatively, compensatory mechanisms (e.g., increases in D₂-like receptors) may affect processes underlying sensitization and conditioned activity.     

Synthesis of Allylthiopyridazine Derivatives and Inhibition of Aflatoxin B<Subscript>1</Subscript>-Induced Hepatotoxicity in Rats

Five kinds of allylthiopyridazine derivatives were synthesized and their chemoprotective activities examined in rats exposed to aflatoxin B1-toxicant. Rats were pretreated with five allylthiopyridazine derivatives at daily oral doses of 50 mg/kg for 10 consecutive days, and during this period with one or three repeated doses of the potent hepatotoxin, aflatoxin B1. The hepatoprotective effects of the allylthiopyridazine derivatives against aflatoxin B1 (1 mg/kg, three times at intervals of 3 days, i.p., or at 3 mg/kg, once at final days, i.p.) administration were showed the significantly normal as compared with control in body and liver weights. Aspartate aminotransferase and alanine aminotransferase levels were markedly elevated after aflatoxin B1 administration, and pretreatment with allylthiopyridazine derivatives, before aflatoxin B1 administration, resulted in decreased levels of these enzymes. In addition, the allylthiopyridazine derivatives, K6 (3-methoxy-), K8 (3-chloro-), K16 (3-ethoxy-) and K17 (3-n-propoxy), induced elevated hepatic GSH levels. Four kinds of allylthiopyridazine derivatives investigated were effective against aflatoxin B1-induced hepatotoxicity.     

Characterization of dopamine D<Subscript>1</Subscript> and D<Subscript>2</Subscript> receptor function in socially housed cynomolgus monkeys self-administering cocaine

Rationale Social rank has been shown to influence dopamine (DA) D₂ receptor function and vulnerability to cocaine self-administration in cynomolgus monkeys. The present studies were designed to extend these findings to maintenance of cocaine reinforcement and to DA D₁ receptors.Objective Examine the effects of a high-efficacy D₁ agonist on an unconditioned behavior (eyeblinking) and a low-efficacy D₁ agonist on cocaine self-administration, as well as the effects of cocaine exposure on D₂ receptor function across social ranks, as determined by positron emission tomography (PET).Methods Effects of the high-efficacy D₁ agonist SKF 81297 and cocaine (0.3–3.0 mg/kg) on spontaneous blinking were characterized in eight monkeys during 15-min observation periods. Next, the ability of the low-efficacy D₁ agonist SKF 38393 (0.1–17 mg/kg) to decrease cocaine self-administration (0.003–0.1 mg/kg per injection, IV) was assessed in 11 monkeys responding under a fixed-ratio 50 schedule. Finally, D₂ receptor levels in the caudate and putamen were assessed in nineteen monkeys using PET.Results SKF 81297, but not cocaine, significantly increased blinking in all monkeys, with slightly greater potency in dominant monkeys. SKF 38393 dose-dependently decreased cocaine-maintained response rates with similar behavioral potency and efficacy across social rank. After an extensive cocaine self-administration history, D₂ receptor levels did not differ across social ranks.Conclusions These results suggest that D₁ receptor function is not substantially influenced by social rank in monkeys from well-established social groups. While an earlier study showed that dominant monkeys had higher D₂ receptor levels and were less sensitive to the reinforcing effects of cocaine during initial exposure, the present findings indicate that long-term cocaine use changed D₂ receptor levels such that D₂ receptor function and cocaine reinforcement were not different between social ranks. These findings suggest that cocaine exposure attenuated the impact of social housing on DA receptor function.     

Synthesis,characterization and biological evaluation of dihydropyrimidine derivatives

A series of dihydropyrimidines containing quinoline were prepared under conventional heating and microwave irradiation. The structures of newly synthesized compounds were established based on analytical and spectral studies. Further these compounds were evaluated for their antioxidant, antifungal and antibacterial activities. Most of the compounds showed moderate to good activity when compared with standard.     

The effects of the neurosteroids: pregnenolone,progesterone and dehydroepiandrosterone on muscarinic receptor-induced responses in <Emphasis Type="Italic">Xenopus</Emphasis> oocytes expressing M<Subscript>1</Subscript> and M<Subscript>3</Subscript> receptors

The neurosteroids pregnenolone, progesterone, and dehydroepiandrosterone (DHEA) occur naturally in the nervous system. They act on neural tissues, participate in neuronal signaling, and are reported to alter neuronal excitability via nongenomic mechanisms. Muscarinic receptors have important roles in neuronal functions in the brain and autonomic nervous system. In this study, we investigated the effects of pregnenolone, progesterone, and DHEA on M₁ and M₃ muscarinic receptors using the Xenopus oocyte expression system. Pregnenolone and progesterone inhibited the acetylcholine (ACh)-mediated responses of M₁ and M₃ receptors expressed in Xenopus oocytes, whereas DHEA did not. The half-maximal inhibitory concentrations (IC₅₀) for pregnenolone inhibition of M₁ receptor- and M₃ receptor-mediated currents were 11.4 and 6.0 M respectively; the IC₅₀ values for progesterone inhibition of M₁ receptor- and M₃ receptor-mediated currents were 2.5 and 3.0 M respectively. The selective protein kinase C (PKC) inhibitor GF109203X had little effect on the pregnenolone or progesterone inhibition of the ACh-induced currents in Xenopus oocytes expressing M₁ or M₃ receptors. The inhibitory effects of pregnenolone and progesterone were overcome at higher concentrations of ACh. Pregnenolone and progesterone inhibited the [³H]quinuclidinyl benzilate (QNB) binding to M₁ and M₃ receptor expressed in Xenopus oocytes, and Scatchard plot analysis of [³H]QNB binding revealed that pregnenolone and progesterone altered the K_d value and the B_max, indicating noncompetitive inhibition. In conclusion, pregnenolone and progesterone inhibited M₁ and M₃ receptor functions noncompetitively by the mechanism independent of PKC and by interfering with ACh binding to the receptors.     

Synthesis, antibacterial, and antifungal activities of biolabile (E)-1-(4-morpholinophenyl)-3-aryl-prop-2-en-1-ones

Abstract  A collection of biolabile (E)-1-(4-morpholinophenyl)-3-aryl-prop-2-en-1-ones 8–13 are synthesized, characterized by melting point, elemental analysis, mass spectroscopy (MS), Fourier-transform infrared (FT-IR), and ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopic data and evaluated for their in vitro antibacterial and antifungal activities. Compounds 8–13 exerted a wide range of antibacterial activities against all tested Gram-positive and Gram-negative bacterial strains. All the compounds 8–13 were more active against Pseudomonas. Of the synthesized compounds, compounds 9 and 11 exhibited a wide range of antibacterial activities against Staphylococcus aureus, β-Heamolytic streptococcus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas. Compounds 10, 12, and 13 exerted strong antifungal activities against all tested fungal strains, namely Aspergillus flavus, Mucor, Rhizopus, and Microsporum gypsuem. Graphical Abstract        

Occupancy of dopamine D<Subscript>1</Subscript>, D<Subscript>2</Subscript> and serotonin<Subscript>2A</Subscript> receptors in schizophrenic patients treated with flupentixol in comparison with risperidone and haloperidol

Rationale Flupentixol (FLX) has been used as a neuroleptic for nearly 4 decades. In vitro data show comparable affinity to dopamine D₂, D₁ and 5-HT_2A receptors and recently, FLX showed to be not inferior to risperidone in schizophrenic patients with predominant negative symptomatology, which was implicated with flupentixol’s interaction with 5-HT_2A and/or D₁ receptors. Objectives To assess in vivo receptor occupancy (RO) in patients clinically treated with FLX (n = 13, 5.7 ± 1.4 mg/day) in comparison with risperidone (RIS, n = 11, 3.6 ± 1.3 mg/day) and haloperidol (HAL, n = 11, 8.5 ± 5.5 mg/day). Materials and methods Each patient underwent two PET scans with 3-N-[¹¹C]methylspiperone (target: frontal 5-HT_2A), [¹¹C]SCH23390 (striatal D₁) or [¹¹C]raclopride (striatal D₂). RO was calculated as the percentage reduction of specific binding in comparison with healthy controls. Results D₂-RO under FLX was between 50% and 70%, indicating an ED₅₀ of about 0.7 ng/ml serum. 5-HT_2A and D₁-RO was 20 ± 10% and 20 ± 5% (mean, SEM). Under HAL, D₁-RO was 14 ± 6% and under RIS not significantly different from zero. Conclusions We were able to demonstrate a moderate 5-HT_2A and D₁ occupancy under clinically relevant doses of flupentixol, albeit lower than expected from in vitro data and clearly below saturation. Therefore, if flupentixol’s efficacy on negative symptoms is based on its interaction with 5-HT_2A and/or D₁ receptors, it should be highly dependent on serum concentration and thus on dosage and metabolism. However, these data suggest that mechanisms other than D₁ or 5-HT_2A antagonism may contribute to flupentixol’s efficacy on negative symptoms.     

Antidepressant-like effects of agomelatine,melatonin and the NK<Subscript>1</Subscript> receptor antagonist GR205171 in impulsive-related behaviour in rats

Rationale Substance P receptor [neurokinin₁ (NK₁-R)] antagonists and melatonin_1/2 receptor (MT_1/2-R) agonists have been claimed to be potential antidepressants (ADs). In animals, these compounds are active in validated models responsive to ADs, such as forced swimming test and chronic mild stress paradigms. Classical AD drugs are also known to be effective in pathologies characterized by an impulse control deficiency. In line with this clinical observation, previous studies demonstrated that classical ADs increased the capacity to wait for food reward in rats subjected to a paradigm aimed at assessing impulsive-related behaviour. Objectives This study was conducted to investigate the effects of two MT_1/2-R agonists, melatonin and agomelatine, and a NK₁-R antagonist, GR205171, on tolerance to delay of food reward in rats. Methods Fasting rats were trained in a T-maze and allowed to choose between two magnitudes of reward: immediate but small reward (two pellets) vs 25-s delayed but large reward (ten pellets). Under this alternative, vehicle-injected rats selected the large-but-delayed reinforcer in less than 40% of the trials. Results Like the established ADs clomipramine (8 mg kg⁻¹, i.p.) and fluvoxamine (4 mg kg⁻¹, i.p.), melatonin (3 and 10 mg kg⁻¹, i.p.), agomelatine (10 and 30 mg kg⁻¹, i.p.) and GR205171 (30 mg kg⁻¹ but not 10 mg kg⁻¹, s.c.) significantly increased the number of choices of the large-but-delayed reward. The effect of melatonin (3 mg kg⁻¹, i.p.) was not counteracted by the MT_1/2-R antagonist S22153 (40 mg kg⁻¹, i.p.) that exerted no effect on its own. Conclusion These results suggest that MT_1/2-R agonists and NK₁-R antagonists enhance rats' tolerance to delay of gratification, an effect which may reflect their ability to improve impulse control. Further investigations are necessary to clarify the neurobiological mechanisms responsible for this effect.     

Synthesis and anti-measles virus activity of new isoquinolin-4-one derivatives

Despite intense efforts to increase vaccine coverage, measles virus (MV) still causes significant morbidity and mortality in the world sometimes as a results of severe, chronic and lethal diseases. In an effort to develop therapies to supplement immunization strategies a number of 1-oxo-2-[[(1E)-phenylmethylene]amino]-1,2-dihydroisoquinoline-4-carboxylic acid derivatives were synthesized and evaluated for anti-measles activity. The substituents on the aromatic ring were chosen in order to evaluate the influence of electron-withdrawing or electron-donating effects on the electronic density of the aromatic moiety. We also evaluated the introduction of a vinyl chain between the exocyclic nitrogen and phenyl moiety. The biological results allow to outline some preliminary considerations on structure-activity relationship.     

A detailed behavioral analysis of the acute motor effects of caffeine in the rat: involvement of adenosine A<Subscript>1</Subscript> and A<Subscript>2A</Subscript> receptors

Rationale There is no consensus on the contribution of adenosine A₁ and A_2A receptor blockade to motor-activating effects of caffeine.Objective Our aim was to use a detailed and continuous observational method to compare the motor effects induced by caffeine with those induced by selective A₁ and A_2A receptor antagonists.Methods The behavioral repertoire induced by systemic administration of caffeine (3, 10, and 30 mg/kg), A₁ receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT; 1.2, 4.8 and 7.2 mg/kg), and A_2A receptor antagonist 3-(3-hydroxypropyl)-8-(m-methoxystyryl)-7-methyl-1-propargylxanthine phosphate disodium salt (MSX-3; 1, 3, and 10 mg/kg) was analyzed. The effects of pretreatment with the selective A₁ receptor agonist N ⁶-cyclopentyladenosine (CPA; 0.1 mg/g) and the selective A_2A receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5′-N-ethylcarboxyamidoadenosine (CGS 21680; 0.2 mg/kg) on the pattern of motor activation induced by caffeine, CPT, or MSX-3 were also examined.Results The pattern of behavioral activation induced by caffeine was better mimicked by CPT than by MSX-3. Coadministration of CPT and MSX-3 gave different results depending on the dose and the type of behavioral response. CPA was more effective at decreasing the activating effects of caffeine and CPT than those of CGS 21680. On the other hand, CGS 21680 was more effective at decreasing the activating effects of MSX-3 than those of caffeine or CPT. Factor analysis revealed a complex three-dimensional behavioral profile for caffeine that was similar to the profile for CPT and was different from the profile for MSX-3.Conclusions The results indicate a predominant role for A₁ receptors in the motor-activating effects of acutely administered caffeine.     

Non-uniform blockade of intrastriatal D<Subscript>2</Subscript>/D<Subscript>3</Subscript> receptors by risperidone and amisulpride

Rationale Atypical antipsychotic drugs have been shown to preferentially affect extrastriatal (mesolimbic) D₂/D₃ receptors over those within the striatum (nigrostriatal). The striatum does not contain exclusively nigrostriatal dopamine tracts, however. The caudate nucleus and ventral parts of the striatum primarily contain limbic and associative dopamine pathways more relevant to psychosis. Objectives We tested the hypothesis that two pharmacologically distinct atypical antipsychotic drugs, amisulpride and risperidone, would preferentially occupy of D₂/D₃ dopamine receptors in limbic and associative regions of the striatum. Methods Eight amisulpride-treated patients, six risperidone-treated patients and six age- and sex-matched healthy controls were recruited. Dynamic SPET studies were performed after bolus injection of [¹²³I]epidepride. Binding potential (BP) images were generated using a modified Logan method and aligned between subjects. Regions of interest (ROIs) were placed around head of caudate and putamen bilaterally on an average BP map derived from aligned control images. These ROIs were then applied user-independently to the BP maps for each subject to calculate BP for head of caudate and putamen. Mean occupancy of D₂/D₃ receptors in each ROI was determined by reference to the drug-free healthy volunteer group. Occupancy values for head of caudate and putamen were compared using paired Student’s t test. Results D₂/D₃ receptor occupancy was 42% in caudate and 31% in putamen for risperidone (t=5.9, df=11, p=0.0001) and 51% in caudate and 37% in putamen for amisulpride (t=11.1, df=15, p<0.0001). Conclusions Amisulpride and risperidone both show selective occupancy for limbic and associative D₂/D₃ receptors within the striatum.     

Functional serotonin 5-HT<Subscript>4</Subscript> receptors in porcine and human ventricular myocardium with increased 5-HT<Subscript>4</Subscript> mRNA in heart failure

Serotonin (5-hydroxytryptamine, 5-HT) increases contractile force and elicits arrhythmias through 5-HT₄ receptors in porcine and human atrium, but its ventricular effects are unknown. We now report functional 5-HT₄ receptors in porcine and human ventricle. 5-HT₄ mRNA levels were determined in porcine and human ventricles and contractility studied in ventricular trabeculae. Cyclic AMP-dependent protein kinase (PKA) activity was measured in porcine ventricle. Porcine and human ventricles expressed 5-HT₄ receptor mRNA. Ventricular 5-HT_4(b) mRNA was increased by four times in 20 failing human hearts compared with five donor hearts. 5-HT increased contractile force maximally by 16% (EC₅₀=890 nM) and PKA activity by 20% of the effects of (–)-isoproterenol (200 M) in ventricular trabeculae from new-born piglets in the presence of the phosphodiesterase-inhibitor 3-isobutyl-1-methylxanthine. In ventricular trabeculae from adult pigs (3-isobutyl-1-methylxanthine present) 5-HT increased force by 32% (EC₅₀=60 nM) and PKA activity by 39% of (–)-isoproterenol. In right and left ventricular trabeculae from failing hearts, exposed to modified Krebs solution, 5-HT produced variable increases in contractile force in right ventricular trabeculae from 4 out of 6 hearts and in left ventricular trabeculae from 3 out of 3 hearts— range 1–39% of (–)-isoproterenol, average 8%. In 11 left ventricular trabeculae from the failing hearts of four -blocker-treated patients, pre-exposed to a relaxant solution with 0.5 mM Ca²⁺ and 1.2 mM Mg²⁺ followed by a switch to 2.5 mM Ca²⁺ and 1 mM Mg²⁺, 5-HT (1–100 M, 3-isobutyl-1-methylxanthine present) consistently increased contractile force and hastened relaxation by 46% and 25% of (–)-isoproterenol respectively. 5-HT caused arrhythmias in three trabeculae from 3 out of 11 patients. In the absence of phosphodiesterase inhibitor, 5-HT increased force in two trabeculae, but not in another six trabeculae from 4 patients. All 5-HT responses were blocked by 5-HT₄ receptor antagonists. We conclude that phosphodiesterase inhibition uncovers functional ventricular 5-HT₄ receptors, coupled to a PKA pathway, through which 5-HT enhances contractility, hastens relaxation and can potentially cause arrhythmias.The first two authors contributed equally to the present work     

Transformation of ginseng saponins to ginsenoside rh<Subscript>2</Subscript> by acids and human intestinal bacteria and biological activities of their transformants

When ginseng water extract was incubated at 60 degrees C in acidic conditions, its protopanaxadiol ginsenosides were transformed to ginsenoside Rg3 and delta20-ginsenoside Rg3. However, protopanaxadiol glycoside ginsenosides Rb1, Rb2 and Rc isolated from ginseng were mostly not transformed to ginsenoside Rg3 by the incubation in neutral condition. The transformation of these ginsenosides to ginsenoside Rg3 and delta20-ginsenoside Rg3 was increased by increasing incubation temperature and time in acidic condition: the optimal incubation time and temperature for this transformation was 5 h and 60 degrees C resepectively. The transformed ginsenoside Rg3 and delta20-ginsenoside Rg3 were metabolized to ginsenoside Rh2 and delta20-ginsenoside Rh2, respectively, by human fecal microflora. Among the bacteria isolated from human fecal microflora, Bacteroides sp., Bifidobacterium sp. and Fusobacterium sp. potently transformed ginsenoside Rg3 to ginsenoside Rh2. Acid-treated ginseng (AG) extract, fermented AG extract, ginsenoside Rh2 and protopanaxadiol showed potent cytotoxicity against tumor cell lines. AG extract, fermented AG extract and protopanaxadiol potently inhibited the growth of Helicobacter pylori.