Enhancement of Haloperidol-Induced Catalepsy by GPR143, an L-Dopa Receptor, in Striatal Cholinergic Interneurons

Dopamine neurons play crucial roles in pleasure, reward, memory, learning, and fine motor skills and their dysfunction is associated with various neuropsychiatric diseases. Dopamine receptors are the main target of treatment for neurologic and psychiatric disorders. Antipsychotics that antagonize the dopamine D2 receptor (DRD2) are used to alleviate the symptoms of these disorders but may also sometimes cause disabling side effects such as parkinsonism (catalepsy in rodents). Here we show that GPR143, a G-protein-coupled receptor for L-3,4-dihydroxyphenylalanine (L-DOPA), expressed in striatal cholinergic interneurons enhances the DRD2-mediated side effects of haloperidol, an antipsychotic agent. Haloperidol-induced catalepsy was attenuated in male Gpr143 gene-deficient (Gpr143-/y ) mice compared with wild-type (Wt) mice. Reducing the endogenous release of L-DOPA and preventing interactions between GPR143 and DRD2 suppressed the haloperidol-induced catalepsy in Wt mice but not Gpr143-/y mice. The phenotypic defect in Gpr143-/y mice was mimicked in cholinergic interneuron-specific Gpr143-/y (Chat-cre;Gpr143flox/y ) mice. Administration of haloperidol increased the phosphorylation of ribosomal protein S6 at Ser240/244 in the dorsolateral striatum of Wt mice but not Chat-cre;Gpr143flox/y mice. In Chinese hamster ovary cells stably expressing DRD2, co-expression of GPR143 increased cell surface expression level of DRD2, and L-DOPA application further enhanced the DRD2 surface expression. Shorter pauses in cholinergic interneuron firing activity were observed after intrastriatal stimulation in striatal slice preparations from Chat-cre;Gpr143flox/y mice compared with those from Wt mice. Together, these findings provide evidence that GPR143 regulates DRD2 function in cholinergic interneurons and may be involved in parkinsonism induced by antipsychotic drugs.

Mygalin, an Acanthoscurria gomesiana spider-derived synthetic, modulates haloperidol-induced cataleptic state in mice

BACKGROUND

Haloperidol (HAL) is an antipsychotic used in the treatment of schizophrenia. However, adverse effects are observed in the extrapyramidal tracts due to its systemic action. Natural compounds are among the treatment alternatives widely available in Brazilian biodiversity. Mygalin (MY), a polyamine that was synthesized from a natural molecule present in the hemolymph of the Acanthoscurria gomesian spider, may present an interesting approach.

AIMS

This study aimed to evaluate the effect of MY in mice subjected to HAL-induced catalepsy.

METHODS

Male Swiss mice were used. Catalepsy was induced by intraperitoneal administration of HAL (0.5 mg/kg - 1 mL/Kg) diluted in physiological saline. To assess the MY effects on catalepsy, mice were assigned to 4 groups: (1) physiological saline (NaCl 0.9 %); (2) MY at 0.002 mg/Kg; (3) MY at 0.02 mg/Kg; (4) MY at 0.2 mg/Kg. MY or saline was administered intraperitoneally (IP) 10 min b HAL before saline. Catalepsy was evaluated using the bar test at 15, 30, 60, 90, and 120 min after the IP administration of HAL.

RESULTS

The latency time in the bar test 15, 30, 60, and 90 min increased (p < 0.05) after IP administration of HAL compared to the control group. Catalepsy was attenuated 15, 30, 90, and 120 min (p < 0.05) after the IP-administration of MY at 0.2 mg/Kg; while MY at 0.02 mg/Kg attenuated catalepsy 15 min after the HAL treatment. Our findings showed that MY attenuates the HAL-induced cataleptic state in mice.

Local field potential (LFP) power and phase-amplitude coupling (PAC) changes in the striatum and motor cortex reflect neural mechanisms associated with bradykinesia and rigidity during D2R suppression in an animal model

Impairments in motor control are the primary feature of Parkinson's disease, which is caused by dopaminergic imbalance in the basal ganglia. Identification of neural biomarkers of dopamine D2 receptor (D2R) suppression would be useful for monitoring the progress of neuropathologies and effects of treatment. Male Swiss albino ICR mice were deeply anesthetized, and electrodes were implanted in the striatum and motor cortex to record local field potential (LFP). Haloperidol (HAL), a D2R antagonist, was administered to induce decreased D2R activity. Following HAL treatment, the mice showed significantly decreased movement velocity in open field test, increased latency to descend in a bar test, and decreased latency to fall in a rotarod test. LFP signals during HAL-induced immobility (open field test) and catalepsy (bar test) were analyzed. Striatal low-gamma (30.3-44.9 Hz) power decreased during immobility periods, but during catalepsy, delta power (1-4 Hz) increased, beta1(13.6-18 Hz) and low-gamma powers decreased, and high-gamma (60.5-95.7 Hz) power increased. Striatal delta-high-gamma phase-amplitude coupling (PAC) was significantly increased during catalepsy but not immobility. In the motor cortex, during HAL-induced immobility, beta1 power significantly increased and low-gamma power decreased, but during HAL-induced catalepsy, low-gamma and beta1 powers decreased and high-gamma power increased. Delta-high-gamma PAC in the motor cortex significantly increased during catalepsy but not during immobility. Altogether, the present study demonstrated changes in delta, beta1 and gamma powers and delta-high-gamma PAC in the striatum and motor cortex in association with D2R suppression. In particular, delta power in the striatum and delta-high-gamma PAC in the striatum and motor cortex appear to represent biomarkers of neural mechanisms associated with bradykinesia and rigidity.

Behavioral effects induced by the cannabidiol analogs HU-502 and HU-556

Cannabidiol is a phytocannabinoid that lacks the psychotomimetic properties of Δ9-tetrahydrocannabinol (THC), the main psychoactive Cannabis sativa component. Cannabidiol has several potential therapeutic properties, including anxiolytic, antidepressant, and antipsychotic; however, cannabidiol has low oral bioavailability, which can limit its clinical use. Here, we investigated if two cannabidiol analogs, HU-502 and HU-556, would be more potent than cannabidiol in behavioral tests predictive of anxiolytic, antidepressant, and antipsychotic effects. Different doses (0.01-3 mg/kg; intraperitoneally) of HU-556 and HU-502 were tested in male Swiss mice submitted to the elevated plus maze (EPM), forced swimming test (FST), and amphetamine-induced-prepulse inhibition (PPI) disruption and hyperlocomotion. Cannabidiol is effective in these tests at a dose range of 15-60 mg/kg in mice. We also investigated if higher doses of HU-556 (3 and 10 mg/kg) and HU-502 (10 mg/kg) produced the cannabinoid tetrad (hypolocomotion, catalepsy, hypothermia, and analgesia), which is induced by THC-like compounds. HU-556 (0.1 and 1 mg/kg) increased the percentage of open arm entries (but not time) in the EPM, decreased immobility time in the FST, and attenuated amphetamine-induced PPI disruption. HU-502 (1 and 3 mg/kg) decreased amphetamine-induced hyperlocomotion and PPI impairment. HU-556, at high doses, caused catalepsy and hypolocomotion, while HU-502 did not. These findings suggest that similar to cannabidiol, HU-556 could induce anxiolytic, antidepressant, and antipsychotic-like effects and that HU-502 has antipsychotic properties. These effects were found at a dose range devoid of cannabinoid tetrad effects.

The selective 5-HT 1A receptor agonist, NLX-112, overcomes tetrabenazine-induced catalepsy and depression-like behavior in the rat

Tetrabenazine, a preferential inhibitor of the vesicular monoamine transporter type 2, depletes the brain monoamines dopamine, serotonin and norepinephrine. Tetrabenazine and deutetrabenazine (Austedo ®) are used to treat chorea associated with Huntington's disease. However, both compounds are known to aggravate Parkinsonism and depression observed in Huntington's disease patients. NLX-112 (a.k.a. befiradol/F13640) is a highly selective, potent and efficacious serotonin 5-HT 1A agonist. In animal models, it has robust efficacy in combating other iatrogenic motor disorders such as L-DOPA-induced dyskinesia and has marked antidepressant-like activity in rodent tests. In the present study, we investigated, in rats, the efficacy of NLX-112 to counteract tetrabenazine-induced catalepsy (a model of Parkinsonism) and tetrabenazine-induced potentiation of immobility in the forced swim test (FST, a model to detect antidepressant-like activity). The prototypical 5-HT 1A agonist, (±)8-OH-DPAT, and the 5-HT 1A partial agonist/dopamine D2 receptor blocker, buspirone, were used as comparators. Both NLX-112 and (±)8-OH-DPAT (0.16-2.5 mg/kg p.o. or s.c., respectively) abolished catalepsy induced by tetrabenazine (2 mg/kg i.p.). In comparison, buspirone (0.63-5.0 mg/kg p.o.) was ineffective and even tended to potentiate tetrabenazine-induced catalepsy at 0.63 mg/kg. In the FST, NLX-112 and (±)8-OH-DPAT (0.63 mg/kg) strongly reduced immobility when administered alone but also significantly opposed potentiation of immobility induced by tetrabenazine (1.5 mg/kg i.p.). Buspirone (0.63 and 2.5 mg/kg p.o.) had no effect by itself or against tetrabenazine. These results strongly suggest that selective and highly efficacious 5-HT 1A agonists, such as NLX-112, may be useful in combating tetrabenazine-induced Parkinsonism and/or depression in Huntington's disease patients.

4-Methoxycinnamic acid attenuates schizophrenia-like behaviors induced by MK-801 in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Scrophularia buergeriana has been used for traditional medicine as an agent for reducing heat in the blood and for nourishing kidney 'Yin'. Therefore, S. buergeriana might be a potential treatment for mental illness, especially schizophrenia, which may be attenuated by supplying kidney Yin and reducing blood heat. In a pilot study, we found that S. buergeriana alleviated sensorimotor gating dysfunction induced by MK-801.

AIM OF THE STUDY

In the present study, we attempted to reveal the active component(s) of S. buergeriana as a candidate for treating sensorimotor gating dysfunction, and we identified 4-methoxycinnamic acid. We explored whether 4-methoxycinnamic acid could affect schizophrenia-like behaviors induced by hypofunction of the glutamatergic neurotransmitter system.

MATERIALS AND METHODS

Mice were treated with 4-methoxycinnamic acid (3, 10, or 30 mg/kg, i.g.) under MK-801-induced schizophrenia-like conditions. The effect of 4-methoxycinnamic acid on schizophrenia-like behaviors were explored using several behavioral tasks. We also used Western blotting to investigate which signaling pathway(s) is involved in the pharmacological activities of 4-methoxycinnamic acid.

RESULTS

4-Methoxycinnamic acid ameliorated MK-801-induced prepulse inhibition deficits, social interaction disorders and cognitive impairment by regulating the phosphorylation levels of PI3K, Akt and GSK-3β signaling in the prefrontal cortex. And there were no adverse effects in terms of catalepsy and motor coordination impairments.

CONCLUSION

Collectively, 4-methoxycinnamic acid would be a potential candidate for treating schizophrenia with fewer adverse effects, especially the negative symptoms and cognitive dysfunctions.

Pharmacokinetics and pharmacodynamics of the synthetic cannabinoid, 5F-MDMB-PICA, in male rats

5F-MDMB-PICA is a popular synthetic cannabinoid associated with analytically confirmed intoxications. In vitro studies show 5F-MDMB-PICA is a potent cannabinoid-1 receptor (CB1) agonist, but little information is available about in vivo pharmacokinetics and pharmacodynamics. To this end, the present study had three aims: 1) to develop a validated method for detection of 5F-MDMB-PICA and its metabolites in rat plasma, 2) to utilize the method for investigating pharmacokinetics of 5F-MDMB-PICA in rats, and 3) to relate 5F-MDMB-PICA pharmacokinetics to pharmacodynamic effects. 5F-MDMB-PICA and its metabolites were quantified using liquid chromatography tandem mass spectrometry (LC-MS/MS) and method validation followed forensic standards. Male Sprague-Dawley rats bearing surgically implanted jugular catheters and subcutaneous (s.c.) temperature transponders received 5F-MDMB-PICA (50, 100, or 200 μg/kg, s.c.) or its vehicle. Blood samples were drawn at 15, 30, 60, 120, 240, and 480 min post-injection, and plasma was assayed using LC-MS/MS. At each blood draw, body temperature, and catalepsy scores were recorded. Maximum plasma concentrations (Cmax) of 5F-MDMB-PICA rose linearly with increasing dose (1.72-6.20 ng/mL), and plasma half-life (t1/2) ranged from 400 to 1000 min 5F-MDMB-PICA-3,3-dimethylbutanoic acid and 5OH-MDMB-PICA were the only metabolites detected, and plasma concentrations were much lower than the parent drug. 5F-MDMB-PICA induced robust hypothermia and catalepsy-like symptoms that were significantly correlated with concentrations of 5F-MDMB-PICA. Radioligand binding in rat brain membranes revealed 5F-MDMB-PICA displays high affinity for CB1 (IC50 = 2 nM) while metabolites do not. In summary, 5F-MDMB-PICA is a potent CB1 agonist in rats whose pharmacodynamic effects are related to circulating concentrations of the parent drug and not its metabolites.

Effects of a Peripherally Restricted Hybrid Inhibitor of CB1 Receptors and iNOS on Alcohol Drinking Behavior and Alcohol-Induced Endotoxemia

Alcohol consumption is associated with gut dysbiosis, increased intestinal permeability, endotoxemia, and a cascade that leads to persistent systemic inflammation, alcoholic liver disease, and other ailments. Craving for alcohol and its consequences depends, among other things, on the endocannabinoid system. We have analyzed the relative role of central vs. peripheral cannabinoid CB1 receptors (CB1R) using a "two-bottle" as well as a "drinking in the dark" paradigm in mice. The globally acting CB1R antagonist rimonabant and the non-brain penetrant CB1R antagonist JD5037 inhibited voluntary alcohol intake upon systemic but not upon intracerebroventricular administration in doses that elicited anxiogenic-like behavior and blocked CB1R-induced hypothermia and catalepsy. The peripherally restricted hybrid CB1R antagonist/iNOS inhibitor S-MRI-1867 was also effective in reducing alcohol consumption after oral gavage, while its R enantiomer (CB1R inactive/iNOS inhibitor) was not. The two MRI-1867 enantiomers were equally effective in inhibiting an alcohol-induced increase in portal blood endotoxin concentration that was caused by increased gut permeability. We conclude that (i) activation of peripheral CB1R plays a dominant role in promoting alcohol intake and (ii) the iNOS inhibitory function of MRI-1867 helps in mitigating the alcohol-induced increase in endotoxemia.

Pharmacological evaluation of vanillic acid in rotenone-induced Parkinson's disease rat model

In the present study, we investigated the anti-Parkinson's effect of vanillic acid (VA) (12 mg/kg, 25 mg/kg, 50 mg/kg p.o.) against rotenone (2 mg/kg s.c.) induced Parkinson's disease (PD) in rats. The continuous administration of rotenone for 35 days resulted in rigidity in muscles, catalepsy, and decrease in locomotor activity, body weight, and rearing behaviour along with the generation of oxidative stress in the brain (rise in the TBARS, and SAG level and reduced CAT, and GSH levels). Co-treatment of VA and levodopa-carbidopa (100 mg/kg + 25 mg/kg p.o.) lead to a significant (P < 0.001) reduction in the muscle rigidity and catalepsy along with a significant (P < 0.001) increase in body weight, rearing behaviour, locomotion and muscle activity as compared to the rotenone-treated group in the dose dependent manner, showing maximum effect at the 50 mg/kg. It also showed reversal of levels of oxidative stress parameters thus, reducing the neuronal oxidative stress. The level of DA was also estimated which showed an increase in the level of DA in the VA plus standard drug treated animals as compared to rotenone treated group. Histopathological evaluation showed a high number of eosinophilic lesions in the rotenone group which were found to be very less in the VA co-treated group. The study thus proved that co-treatment of VA and levodopa-carbidopa, significantly protected the brain from neuronal damage due to oxidative stress and attenuated the motor defects indicating the possible therapeutic potential of VA as a neuroprotective in PD.

Protective effect of Actinidia arguta in MPTP-induced Parkinson's disease model mice

Parkinson's disease (PD) is a neurodegenerative disease characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra. Oxidative stress-induced neuronal death has been identified as one of the major causes of nigrostriatal degeneration in PD. The fruit of Actinidia arguta (A. arguta), known as sarunashi in Japan, has been reported to show beneficial health effects such as antioxidant, anti-inflammatory, anti-mutagenic, and anticholinergic effects. In this study, we investigated the neuroprotective effects of A. arguta in 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP)-induced PD model mice. A. arguta juice was administered to 7-week-old C57BL/6J mice continuously for 10 days before the first MPTP injection. The degeneration of dopaminergic neurons in the substantia nigra was induced by MPTP (30 mg/kg, i. p.) once daily for five consecutive days. We found that the administration of A. arguta ameliorated MPTP-induced motor impairment and suppressed the MPTP-induced reductions of tyrosine hydroxylase-positive neurons and tyrosine hydroxylase protein expression in the substantia nigra. Our findings suggest that taking A. arguta could provide neuroprotection that delays or prevents the neurodegenerative process of PD.

Cannabis sativa terpenes are cannabimimetic and selectively enhance cannabinoid activity

Limited evidence has suggested that terpenes found in Cannabis sativa are analgesic, and could produce an "entourage effect" whereby they modulate cannabinoids to result in improved outcomes. However this hypothesis is controversial, with limited evidence. We thus investigated Cannabis sativa terpenes alone and with the cannabinoid agonist WIN55,212 using in vitro and in vivo approaches. We found that the terpenes α-humulene, geraniol, linalool, and β-pinene produced cannabinoid tetrad behaviors in mice, suggesting cannabimimetic activity. Some behaviors could be blocked by cannabinoid or adenosine receptor antagonists, suggesting a mixed mechanism of action. These behavioral effects were selectively additive with WIN55,212, suggesting terpenes can boost cannabinoid activity. In vitro experiments showed that all terpenes activated the CB1R, while some activated other targets. Our findings suggest that these Cannabis terpenes are multifunctional cannabimimetic ligands that provide conceptual support for the entourage effect hypothesis and could be used to enhance the therapeutic properties of cannabinoids.

Taurine and coenzyme Q10 synergistically prevent and reverse chlorpromazine-induced psycho-neuroendocrine changes and cataleptic behavior in rats

Over the years, mounting evidences have suggested a strong association between chronic chlorpromazine therapy, a popular first-generation antipsychotic drug, and psycho-neuroendocrine changes. In this study, we aim to examine whether treatment with taurine and coenzyme Q10 (COQ-10), compounds with steroidogenic-gonadotropin hormone-enhancing properties, can attenuate the negative impacts of chlorpromazine on steroidogenic, gonadotropin, thyroid and HPA-axis hormones, dopamine levels, catalepsy behavior and neuronal cells of the hypothalamus and pituitary gland in the preventive and reversal treatments in male Wister rats. In the drug treatment alone or preventive protocol, rats received oral administration of saline (10 mL/kg), taurine (150 mg/kg/day), COQ-10 (10 mg/kg/day), or both (taurine + COQ-10/day) alone for 56 consecutive days, or in combination with oral chlorpromazine (30 mg/kg/day) treatment from days 29 to 56. In the reversal protocol, the animals received chlorpromazine or saline for 56 days prior to taurine, COQ-10, or the combination from days 29 to 56. Thereafter, serum prolactin, steroidogenic (testosterone, estrogen, progesterone), gonadotropin (luteinizing hormone, LH, follicle-stimulating hormone, FSH), thyroid (thyrotropin-stimulating hormone, tetraiodothyronine, triiodothyronine) hormones, corticosterone, brain dopamine levels and cataleptic behavior were investigated. The histopathological features of the hypothalamus and pituitary gland were also evaluated. Taurine, COQ-10, or their combination prevented and reversed chlorpromazine-induced hyperprolactinemia, decrease in FSH, LH, testosterone, progesterone and dopamine concentrations, as well as the increase in estrogen levels. Taurine and COQ-10 reduced the changes in thyroid hormones, corticosterone release, histological distortions of the hypothalamus and the pituitary gland of chlorpromazine-treated rats. Taurine and COQ-10 attenuated chlorpromazine-induced catalepsy. The study showed that taurine and COQ-10 prevented and reversed chlorpromazine-induced changes in reproductive, thyroid hormones, dopamine level, corticosterone release, neurodegenerations, and cataleptic behavior in rats.

Altered Functional Connectivity of the Orbital Cortex and Striatum Associated with Catalepsy Induced by Dopamine D1 and D2 Antagonists

The dopamine system plays an important role in regulating many brain functions, including the motor function. The blockade of dopamine receptors results in a serious motor dysfunction, such as catalepsy and Parkinsonism. However, the neuronal mechanism underlying the drug-induced motor dysfunction is not well understood. Here, we examine brain-wide activation patterns in Fos-enhanced green fluorescent protein reporter mice that exhibit cataleptic behavior induced by SCH39166, a dopamine D1-like receptor antagonist, and raclopride, a dopamine D2-like receptor antagonist. Support vector classifications showed that the orbital cortex (ORB) and striatum including the caudoputamen (CP) and nucleus accumbens (ACB), prominently contribute to the discrimination between brains of the vehicle-treated and both SCH39166- and raclopride-treated mice. Interregional correlations indicated that the increased functional connectivity of functional networks, including the ORB, CP, and ACB, is the common mechanism underlying SCH39166- and raclopride-induced cataleptic behavior. Moreover, the distinct mechanisms in the SCH39166- and raclopride-induced cataleptic behaviors are the decreased functional connectivity between three areas above and the cortical amygdala, and between three areas above and the anterior cingulate cortex, respectively. Thus, the alterations of functional connectivity in diverse brain regions, including the ORB, provide new insights on the mechanism underlying drug-induced movement disorders.

Effect of M. chamomilla L. tea on chlorpromazine induced catalepsy: A neuroprotective study

We determined anti-Parkinson's activity of M. chamomilla L. tea in chlorpromazine (CPZ) developed investigational animal model. In this research, effects of M. chamomilla L. tea 2.14ml/ kg P.O were studied on cataleptic behavior and its effect on brain histopathological changes and immunohistochemistry (IHC) in rats. The experimental design was developed by administering CPZ (3mg/kg, I/P) for twenty-one days to produce Parkinson's disease-like symptoms to 4 animal groups. We observed that chlorpromazine significantly produced motor dysfunctions (catalepsy) in a time period of twenty-one days. The M. chamomilla L. significantly (P<0.005) minimized/shorten/taper down catalepsy in rats just like standard group (Levodopa/carbidopa treated group). The maximum reduction was observed from both treated and standard groups on the 21st day. M. chamomilla L. treated rats mid brain sections showed presence of proliferative blood vessels, increase cellularity with reactive glial cells as compared to CPZ group. Furthermore, immunostaining CD68 & CD21 of M. chamomilla L. treated rats mid brain region showed few CD68 cells & no polymorphs neutrophils after CD21 staining. Thus, this research work disclosed the neuroprotective effect of M. chamomilla L. tea against Parkinson's disease-like symptoms or anti-Parkinson's activity induced by CPZ.

Dual Target Ligands with 4-tert-Butylphenoxy Scaffold as Histamine H3 Receptor Antagonists and Monoamine Oxidase B Inhibitors

Dual target ligands are a promising concept for the treatment of Parkinson's disease (PD). A combination of monoamine oxidase B (MAO B) inhibition with histamine H₃ receptor (H₃R) antagonism could have positive effects on dopamine regulation. Thus, a series of twenty-seven 4-tert-butylphenoxyalkoxyamines were designed as potential dual-target ligands for PD based on the structure of 1-(3-(4-tert-butylphenoxy)propyl)piperidine (DL76). Probed modifications included the introduction of different cyclic amines and elongation of the alkyl chain. Synthesized compounds were investigated for human H₃R (hH₃R) affinity and human MAO B (hMAO B) inhibitory activity. Most compounds showed good hH₃R affinities with K_i values below 400 nM, and some of them showed potent inhibitory activity for hMAO B with IC₅₀ values below 50 nM. However, the most balanced activity against both biological targets showed DL76 (hH₃R: K_i = 38 nM and hMAO B: IC₅₀ = 48 nM). Thus, DL76 was chosen for further studies, revealing the nontoxic nature of DL76 in HEK293 and neuroblastoma SH-SY5Ycells. However, no neuroprotective effect was observed for DL76 in hydrogen peroxide-treated neuroblastoma SH-SY5Y cells. Furthermore, in vivo studies showed antiparkinsonian activity of DL76 in haloperidol-induced catalepsy (Cross Leg Position Test) at a dose of 50 mg/kg body weight.

Chronic oral treatment with risperidone impairs recognition memory and alters brain-derived neurotrophic factor and related signaling molecules in rats

Antipsychotic drugs (APDs) are essential for the treatment of schizophrenia and other neuropsychiatric illnesses such as bipolar disease. However, they are also extensively prescribed off-label for many other conditions, a practice that is controversial given their potential for long-term side effects. There is clinical and preclinical evidence that chronic treatment with some APDs may lead to impairments in cognition and decreases in brain volume, although the molecular mechanisms of these effects are unknown. The purpose of the rodent studies described here was to evaluate a commonly prescribed APD, risperidone, for chronic effects on recognition memory, brain-derived neurotrophic factor (BDNF), its precursor proBDNF, as well as relevant downstream signaling molecules that are known to influence neuronal plasticity and cognition. Multiple cohorts of adult rats were treated with risperidone (2.5 mg/kg/day) or vehicle (dilute acetic acid solution) in their drinking water for 30 or 90 days. Subjects were then evaluated for drug effects on recognition memory in a spontaneous novel object recognition task and protein levels of BDNF-related signaling molecules in the hippocampus and prefrontal cortex. The results indicated that depending on the treatment period, a therapeutically relevant daily dose of risperidone impaired recognition memory and increased the proBDNF/BDNF ratio in the hippocampus and prefrontal cortex. Risperidone treatment also led to a decrease in Akt and CREB phosphorylation in the prefrontal cortex. These results indicate that chronic treatment with a commonly prescribed APD, risperidone, has the potential to adversely affect recognition memory and neurotrophin-related signaling molecules that support synaptic plasticity and cognitive function.

Experimental study of antiparkinsonian action of the harmine hydrochloride original compound

BACKGROUND

The effects of chemical products on the nervous system have been studied by various scientists. In this work, the antiparkinsonian action of a water-soluble form of harmine hydrochloride was studied. The present studies aim to research antiparkinsonian action of the harmine hydrochloride original compound.

METHODS

To achieve the objective of the study, the authors used haloperidol-induced catalepsy and a method of Parkinson's syndrome (PS) induced by the MPTP (the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) neurotoxin. The experiments were performed on rats and mice which were divided into groups of 10 animals.

RESULTS

It was established that harmine hydrochloride (HH), at a certain dose, eliminated haloperidol-induced catalepsy in rats and reduced oligokinesia and rigidity in the parkinsonism test in mice. Seven days after the experiment, the authors found the presence of rigidity in animals which had received the neurotoxin. It manifested itself in a shortened stride length compared to this parameter in intact controls.

CONCLUSIONS

During the study the efficacy of harmine hydrochloride was equivalent to the effects of levodopa at a certain dose, which suggested that harmine hydrochloride compensated dopamine deficiency in the brain.

Neuroprotective effect of diclofenac on chlorpromazine induced catalepsy in rats

Neuroinflammation plays a key role in progressive degeneration of dopaminergic cells. Upregulation of prostaglandins and free radicals formation are involved in the mechanisms of cell death in Parkinson's disease (PD). The present study aimed to investigate the neuroprotective effect of diclofenac against chlorpromazine (CPZ) induced catalepsy and motor impairment in mice. Adult Wistar rats treated with CPZ (3 mg/kg/day, IP) were orally dosed with diclofenac and L-dopa/carbidopa for 21 days. Catalepsy was measured after 21 days of dosing by using standard bar test at 30, 60, 90, 120 and 180 min then motor performances were assessed via open field test and wire hanging test. Histopathological investigation and determination of dopamine (DA) and 3,4-Dihydroxyphenylacetic acid (DOPAC) levels of rat's brain was also carried out. We found that CPZ treated group exhibited reduced motor impairment after 21 days of treatment in open field and wire hanging test (P < 0.01) as compared to control group. The cataleptic scores of CPZ treated rats were also significantly increased (P < 0.01) after 21 days of chronic dosing, however diclofenac treated groups showed significant reduction in cataleptic scores with improved motor performances. Histopathology of CPZ treated rats showed marked degeneration with architecture distortion in the mid brain region. Dopaminergic degeneration is confirmed by neurochemical results that showed reduced amount of dopamine and DOPAC levels in mid brain. Moreover, histopathological slides of diclofenac treated rats showed improved architecture with reduced gliosis of mid brain region as well as improved dopamine and DOPAC levels were achieved after 21 days dosing of diclofenac. Taken together, the present work provide an evidence that diclofenac ameliorated behavioral performances by mediating neuroprotection against CPZ induced PD via preventing dopaminergic neuronal cell death.

Uncovering the psychoactivity of a cannabinoid from liverworts associated with a legal high

Phytochemical studies on the liverwort Radula genus have previously identified the bibenzyl (-)-cis-perrottetinene (cis-PET), which structurally resembles (-)-Δ⁹-trans-tetrahydrocannabinol (Δ⁹-trans-THC) from Cannabis sativa L. Radula preparations are sold as cannabinoid-like legal high on the internet, even though pharmacological data are lacking. Herein, we describe a versatile total synthesis of (-)-cis-PET and its (-)-trans diastereoisomer and demonstrate that both molecules readily penetrate the brain and induce hypothermia, catalepsy, hypolocomotion, and analgesia in a CB1 receptor-dependent manner in mice. The natural product (-)-cis-PET was profiled on major brain receptors, showing a selective cannabinoid pharmacology. This study also uncovers pharmacological differences between Δ⁹-THC and PET diastereoisomers. Most notably, (-)-cis-PET and (-)-trans-PET significantly reduced basal brain prostaglandin levels associated with Δ⁹-trans-THC side effects in a CB1 receptor-dependent manner, thus mimicking the action of the endocannabinoid 2-arachidonoyl glycerol. Therefore, the natural product (-)-cis-PET is a psychoactive cannabinoid from bryophytes, illustrating the existence of convergent evolution of bioactive cannabinoids in the plant kingdom. Our findings may have implications for bioprospecting and drug discovery and provide a molecular rationale for the reported effects upon consumption of certain Radula preparations as moderately active legal highs.

Interplay between adenosine receptor antagonist and cyclooxygenase inhibitor in haloperidol-induced extrapyramidal effects in mice

Antipsychotic drugs are the mainstay of psychotic disorders. The 'typical' antipsychotic agents are commonly employed for the positive symptoms of schizophrenia, though at an expense of extrapyramidal side effects (EPS). In the present study, we employed haloperidol (HP)-induced catalepsy model in mice to evaluate the role of adenosine receptor antagonist and cyclooxygenase (COX) enzyme inhibitor in the amelioration of EPS. HP produced a full blown catalepsy, akinesia and a significant impairment in locomotion and antioxidant status. Pre-treatment with COX inhibitor; naproxen (NPx) and adenosine receptor antagonist; caffeine (CAF), showed a significant impact on HP-induced cataleptic symptoms. Adenosine exerts pivotal control on dopaminergic receptors and is also involved in receptor internalization and recycling. On the other hand, prostaglandins (PGs) are implicated as neuro-inflammatory molecules released due to microglial activation in both Parkinson's disease (PD) and antipsychotics-induced EPS. The involvement of these neuroeffector molecules has led to the possibility of use of CAF and COX inhibitors as therapeutic approaches to reduce the EPS burden of antipsychotic drugs. Both these pathways seem to be interlinked to each other, where adenosine modulates the formation of PGs through transcriptional modulation of COXs. We observed an additive effect with combined treatment of NPx and CAF against HP-induced movement disorder. These effects lead us to propose that neuromodulatory pathways of dopaminergic circuitry need to be explored for further understanding and utilizing the full therapeutic potential of antipsychotic agents.

Antiallergic and antihistaminic actions of Ceasalpinia bonducella seeds: Possible role in treatment of asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Seed kernel of the plant Ceasalpinia bonducella Linn (Caesalpiniacaeae) are used for the treatment of asthma in folk medicine and ancient books.

AIM OF STUDY

To assess the pharmacological efficacy of the plant in asthma and to confine and describe the synthetic constituents from the seeds that are in charge of the action.

MATERIAL AND METHODS

The viability of petroleum ether, ethanol extract and ethyl acetate fraction from ethanol extract of C. bonducella seeds were screened for the treatment of asthma by various methods viz. effect of test drug on clonidine and haloperidol induced catalepsy, milk-induced leukocytosis and eosinophilia, mast cell stabilizing activity in mice and studies on smooth muscle preparation of guinea pig ileum (in-vitro). Column chromatography of active extract was done to pinpoint the active compound followed by structure elucidation by FTIR, GCMS and NMR spectroscopic methods.

RESULTS

Ethyl acetate fraction from ethanol extract of C. bonducella seeds exhibited antihistaminic activity at the dose of 50 and 100 mg/kg, inhibited clonidine-induced catalepsy but not haloperidol-induced catalepsy. Ethyl acetate fraction from ethanol extract significantly inhibited increased leukocyte and eosinophil count due to milk allergen and showed maximum protection against mast cell degranulation by clonidine. The results of guinea pig ileum indicated that the compound 2 methyl, 1 hexadecanol isolated from ethyl acetate fraction of ethanol extract relaxed significantly the ileum muscle strips pre-contracted by which suggests the involvement of β₂-agonists on the relaxation of the tissue. All the results are dose dependent. Active ethyl acetate fraction from ethanol extract showed presence of anti-asthmatic compound, 2-methyl, 1-hexadecanol.

CONCLUSION

The ethyl acetate fraction from ethanol extract of seeds of the plant C. bonducella can inhibit parameters linked to asthma disease.

Celecoxib, a cyclooxygenase-2 inhibitor, offers chemoprevention against reproductive and neurobehavioural abnormalities induced by atrazine in male Wistar rats

The cyclooxygenase-2/prostanoid pathway (COX-2) serves as a potential therapeutic target in various pathological conditions. Thus, the modulatory effect of celecoxib (CXB), a COX-2 inhibitor, in atrazine-induced toxicity was investigated. Five groups (n = 6 rats per group) of adult male Wistar rats received corn oil (2 ml/kg), atrazine (ATZ, 300 mg/kg) and CXB (5.7 mg/kg) respectively and their combinations via the oral route. Results obtained showed reduced (p < 0.05) sperm motility (25.8%) and counts (27.6%), testosterone (29.9%), luteinizing (33%) and follicle stimulating hormones (78.7%) plus elevated total cholesterol (112.3%), triglyceride (115.7%), malondialdehyde levels respectively in ATZ-treated rats. Similarly, ATZ administration causes reduced locomotion (33.6%), spontaneous motor activity (46.6%) and catalepsy effects (157.3%) respectively. However, CXB divided doses moderately reverse reproductive abnormalities, modulate neurobehavioural deficits and slightly preserved COX-2 elevation following ATZ intoxication. Furthermore, histopathology of testis shows improvement in treated rats. Overall, our data suggest chemopreventive actions via pharmacological inhibition of COX-2 activity during ATZ toxicity.

Synthesis and biological evaluation of a series of multi-target N-substituted cyclic imide derivatives with potential antipsychotic effect

In the present study, a series of multi-target N-substituted cyclic imide derivatives which possessed potent dopamine D₂, serotonin 5-HT_1A and 5-HT_2A receptors properties were synthesized and evaluated as potential antipsychotics. Among these compounds, (3aR,4R,7S,7aS)-2-(4-(4-(benzo[b]thiophen-4-yl)piperazin-1-yl)butyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione hydrochloride (3d) held a promising pharmacological profile. 3d not only showed potent and balanced in vitro activities on D₂/5-HT_1A/5-HT_2A receptors, but also endowed with low to moderate activities on 5-HT_2C, H₁, α_1A, M₃ receptors and hERG channel, suggesting a low liability to induce side effects such as weight gain, orthostatic hypotension and QT prolongation. In animal behavioral studies, 3d reduced phencyclidine-induced hyperlocomotion with a high threshold for catalepsy induction. Compound 3d was selected as a potential antipsychotic candidate for further development.

Short- and long-term effects of risperidone on catalepsy sensitisation and acquisition of conditioned avoidance response: Adolescent vs adult rats

The effects of antipsychotic drugs (APDs) on the adolescent brain are poorly understood despite a dramatic increase in prescription of these drugs in adolescents over the past twenty years. Neuronal systems continue to be remodeled during adolescence. Therefore, when given in adolescence, antipsychotic drugs (APDs) have the potential to affect this remodeling. In this study we investigated the effects of chronic 22-day risperidone treatment (1.3mg/kg/day) in both adolescent and adult rats. We examined short- and long-term changes in behaviour (catalepsy, locomotion and conditioned avoidance response (CAR)), and dopaminergic and serotonergic neurochemistry in the striatum and the nucleus accumbens. Here, we report that, both during chronic treatment and after a lengthy drug-free interval, risperidone induced a sensitised cataleptic response regardless of the age of exposure. Selectively in adolescents, risperidone-induced catalepsy was inversely correlated with striatal dopamine turnover immediately after chronic treatment. After a drug-free interval, a significant proportion of rats with prior adolescent risperidone treatment also failed to acquire CAR to a defined criterion. Our data provide evidence that the same chronic risperidone treatment regimen can induce contrasting short- and long-term neural outcomes in the adolescent and adult brains.

Involvement of presynaptic 5-HT1A receptors in the low propensity of brexpiprazole to induce extrapyramidal side effects in rats

Previous studies have shown that partial and full 5-HT_1A receptor agonists reduce antipsychotic-induced catalepsy. Consequently, some antipsychotics combining balanced efficacy between dopamine (DA) D₂ antagonism or partial agonism and 5-HT_1A receptor agonism have a low propensity to induce extrapyramidal side effects (EPS), as reflected by low cataleptogenic activity in rodents. In the present experiments, we attempted to explore the importance of pre- and postsynaptic 5-HT_1A agonistic properties of brexpiprazole and aripiprazole in the context of neurological side-effect liabilities. Additional measures of prefrontal cortical serotonin (5-HT) and DA levels using microdialysis were used to support that brexpiprazole has a preferential agonist effect on presynaptic 5-HT_1A receptors. Brexpiprazole (3.0 and 10mg/kg, p.o.) as well as aripiprazole (8.0 and 30mg/kg, p.o.) failed to induce catalepsy in rats. Brexpiprazole (10mg/kg, p.o.) significantly reduced the cataleptic response induced by haloperidol (0.63mg/kg, s.c.), while aripiprazole (1.0-100mg/kg, p.o.) failed to reverse the effect of haloperidol and only showed a numeric decrease at 10mg/kg, (p.o.). When 5-HT_1A receptors were blocked by the selective antagonist, WAY100635 (1.0mg/kg, s.c.), cataleptogenic properties of brexpiprazole (10mg/kg; p.o), but not aripiprazole (8.0 and 30mg/kg, p.o.) were unmasked. The ("biased") 5-HT_1A receptor agonists F15599 (postsynaptic preference) and F13714 (presynaptic preference) had differential effects on haloperidol-induced catalepsy: F13714 (0.16mg/kg, s.c.) counteracted catalepsy, whereas F15599 (0.040mg/kg, s.c.) had no significant effect at regionally-selective doses. These data support a role of presynaptic 5-HT_1A receptors in the anticataleptic effect of brexpiprazole. The selective 5-HT_2A antagonist M100907 (0.10mg/kg, s.c.) had no effect on haloperidol-induced catalepsy, arguing against a major role of 5-HT_2A receptors in the cataleptogenic profile of brexpiprazole. The findings with brexpiprazole were supported using microdialysis studies: Brexpiprazole (3.0 and 10mg/kg, p.o.) decreased extracellular 5-HT levels in the medial prefrontal cortex (mPFC), while it failed to affect extracellular DA in the same samples, suggesting that the 5-HT_1A agonist properties of brexpiprazole may be preferentially presynaptic. In conclusion, these results confirm that brexpiprazole and aripiprazole have low propensities to induce EPS. However, the low EPS risk of brexpiprazole is more likely dependent on its agonist properties on presynaptic 5-HT_1A receptors, while that of aripiprazole is less sensitive to 5-HT_1A receptor antagonism.

Development and Antiparkinsonian Activity of VU0418506, a Selective Positive Allosteric Modulator of Metabotropic Glutamate Receptor 4 Homomers without Activity at mGlu2/4 Heteromers

Metabotropic glutamate receptor 4 (mGlu4) is emerging as a potential therapeutic target for numerous central nervous system indications, including Parkinson's disease (PD). As the glutamate binding sites among the eight mGlu receptors are highly conserved, modulation of receptor activity via allosteric sites within the receptor transmembrane domains using positive and negative allosteric modulators (PAMs and NAMs, respectively) has become a common strategy. We and others have used PAMs targeting mGlu4 to show that potentiation of receptor signaling induces antiparkinsonian activity in a variety of PD animal models, including haloperidol-induced catalepsy and 6-hydroxydopamine-induced lesion. Recently, mGlu4 has been reported to form heteromeric complexes with other mGlu receptor subtypes, such as mGlu2, and the resulting heteromer exhibits a distinct pharmacological profile in response to allosteric modulators. For example, some mGlu4 PAMs do not appear to potentiate glutamate activity when mGlu2 and mGlu4 are coexpressed, whereas other compounds potentiate mGlu4 responses regardless of mGlu2 coexpression. We report here the discovery and characterization of VU0418506, a novel mGlu4 PAM with activity in rodent PD models. Using pharmacological approaches and Complemented Donor-Acceptor resonance energy transfer (CODA-RET) technology, we find that VU0418506 does not potentiate agonist-induced activity when mGlu2 and mGlu4 are heterodimerized, suggesting that the antiparkinsonian action of mGlu4 PAMs can be induced by compounds without activity at mGlu2/4 heteromers.

Beneficial anti-Parkinson effects of camel milk in Chlorpromazineinduced animal model: Behavioural and histopathological study

Potential roles of natural products have been identified for preventing or treating various diseases. Our aim was to investigate the effectiveness of camel milk in an animal model of Parkinson's disease and compare it with standard treatment (levodopa + carbidopa combination). 40 Wistar albino rats weighing 200-250 gram were divided into four groups of 10 animals each. Group I was kept on water and served as normal control, group II served as negative control, treated with chlorpromazine (5mg/kg i.p.), group III was given camel milk (33ml/kg p.o) and group IV the standard combination of levodopa + carbidopa (100+10mg/kg) respectively, 30 minutes after chlorpromazine treatment. All animals were subjected to the drugs treatment for 30 days. Catalepsy was assessed by Bar test on day 21 and day 30 at 30, 60, 90 and 120 minutes interval. On 30th day animals were sacrificed and whole brains were examined for histopathological changes. The results revealed highly significant (p<0.001) anti-cataleptic effect of camel milk on day 21 and 30 in comparison to chlorpromazine. When compared with standard therapy, the results showed that anti-Parkinson's activity of camel milk was significant (p<0.01) on day 21. However, the difference in activity was non-significant on day 30. Histopathology of the brain showed that administration of camel milk reveals intact architecture with mild degenerative changes than chlorpromazine and levodopa + carbidopa treated animals. In conclusion, camel milk possesses anti-Parkinson's activity. However, its long term efficacy and safety needs to be evaluated clinically.

Immunohistochemical evidence for the involvement of gonadotropin releasing hormone in neuroleptic and cataleptic effects of haloperidol in mice

Blockade of dopamine D2 receptor by haloperidol is attributed for neuroleptic and cataleptic effects; and also for the release of gonadotropin releasing hormone (GnRH) from the hypothalamus. GnRH agonist is reported to exhibit similar behavioural effects as that of haloperidol, and pre-treatment with GnRH antagonist is shown to attenuate the effects of haloperidol, suggesting a possibility that GnRH might mediate the effects of haloperidol. To substantiate such possibility, the influence of haloperidol on GnRH immunoreactivity (GnRH-ir) in the brain was studied in vehicle/antide pre-treated mice by peroxidase-antiperoxidase method. Initially, an earlier reported antide-haloperidol interaction in rat was confirmed in mice, wherein haloperidol (250μg/kg, i.p.) exhibited suppression of conditioned avoidance response (CAR) on two-way shuttle box, and induced catalepsy in bar test; and pre-treatment with antide (50μg/kg, s.c., GnRH antagonist) attenuated both effects of haloperidol. Immunohistochemical study was carried out to identify GnRH-ir in the brain, isolated 1h after haloperidol treatment to mice pre-treated with vehicle/antide. The morphometric analysis of microphotographs of brain sections revealed that haloperidol treatment increased integrated density units of GnRH-ir in various regions of the limbic system. Considering basal GnRH-ir in vehicle treated group as 100%, the increase in GnRH-ir after haloperidol treatment was by 100.98% in the medial septum; 54.26% in the bed nucleus of the stria terminalis; 1152.85% in the anteroventral periventricular nucleus; 120.79% in the preoptic area-organum vasculosum of the lamina terminalis and 138.82% in the arcuate nucleus. Antide did not influence basal and haloperidol induced increase in GnRH-ir in any of the regions. As significant increase in GnRH-ir after haloperidol treatment was observed in such regions of the brain which are reported to directly or indirectly communicate with the hippocampus and basal ganglia, the regions respectively responsible for neuroleptic and cataleptic effects; and as GnRH antagonist eliminated the effects of haloperidol without affecting GnRH-ir, it appears that GnRH released by haloperidol mediates its neuroleptic and cataleptic effects.

NEUROMODULATORY EFFECTS OF THYMOQUINONE IN EXTENUATING OXIDATIVE STRESS IN CHLORPROMAZINE TREATED RATS

The present study was undertaken to evaluate the possible protective effect of thymoquinone on chlorpromazine induced catalepsy, locomotor activity and cerebral oxidative stress in rats. The rats were divided into four groups, each group containing eight animals. The animals were evaluated after repeated administration of chlorpromazine (CPZ) 30 min before the administration of thymoquinone (TQ) for 21 days. Catalepsy was assessed using block method whereas the locomotor activity was assessed using acceleratory rotarod and actophotometer. Markers of oxidative stress parameters (LPO, GSH, GPx, GR, GST and CAT) were evaluated in the brain of rats. The cataleptic scores were significantly increased in CPZ treated rats when compared with normal control rats. Oral administration of TQ (5 and 10 mg/kg) significantly decreased cataleptic scores when compared with chlorpromazine (CPZ) treated rats. The muscle coordination and spontaneous locomotor activity was significantly decreased in CPZ treated rats when compared with normal control rats. Treatment with TQ significantly improved the muscle coordination and spontaneous locomotor activity when compared with CPZ treated rats. TQ treated rats significantly reduced the elevated levels of lipid peroxidation (LPO), increased levels of antioxidant enzymes i.e., reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and catalase (CAT) when compared with CPZ treated rats. The results clearly suggest that supplementation with TQ can be used to preclude CPZ induced extrapyramidal side effects and may find a role in reducing the oxidative stress.

A dopamine D2 receptor-DISC1 protein complex may contribute to antipsychotic-like effects

Current antipsychotic drugs primarily target dopamine D2 receptors (D2Rs), in conjunction with other receptors such as those for serotonin. However, these drugs have serious side effects such as extrapyramidal symptoms (EPS) and diabetes. Identifying a specific D2R signaling pathway that could be targeted for antipsychotic effects, without inducing EPS, would be a significant improvement in the treatment of schizophrenia. We report here that the D2R forms a protein complex with Disrupted in Schizophrenia 1 (DISC1) that facilitates D2R-mediated glycogen synthase kinase (GSK)-3 signaling and inhibits agonist-induced D2R internalization. D2R-DISC1 complex levels are increased in conjunction with decreased GSK-3α/β (Ser21/9) phosphorylation in both postmortem brain tissue from schizophrenia patients and in Disc1-L100P mutant mice, an animal model with behavioral abnormalities related to schizophrenia. Administration of an interfering peptide that disrupts the D2R-DISC1 complex successfully reverses behaviors relevant to schizophrenia but does not induce catalepsy, a strong predictor of EPS in humans.

Sex differences in antinociceptive tolerance to delta-9-tetrahydrocannabinol in the rat

BACKGROUND

Sex differences in cannabinoid effects have been reported in rodents, with adult females typically being more sensitive than adult males. The present study compared the development of antinociceptive tolerance to delta-9-tetrahydrocannabinol (THC) in adult, gonadally intact female vs. male rats.

METHODS

Cumulative dose-effect curves were obtained for THC (1.0-18 mg/kg i.p.) on warm water tail withdrawal and paw pressure tests. Vehicle or the sex-specific ED80 dose for THC was administered twice daily for 9 days; THC dose-effect curves were then re-determined.

RESULTS

On the pre-chronic test day, THC was significantly more potent in females than males in producing antinociception on the tail withdrawal and paw pressure tests. After 9 days of twice-daily THC treatment (5.4 mg/kg/injection in females and 7.6 mg/kg/injection in males), THC potency on both tests decreased more in females than males. On the tail withdrawal test, chronic THC produced 4.2- vs. 2.8-fold increases in ED50 values in females vs. males, respectively. On the paw pressure test, chronic THC produced 4.4- vs. 2.9-fold increases in ED50 values in females vs. males, respectively. Chronic THC treatment did not significantly disrupt estrous cycling in females.

CONCLUSIONS

These results demonstrate that--even when sex differences in acute THC potency are controlled--females develop more antinociceptive tolerance to THC than males. Given the importance of drug tolerance in the development of drug dependence, these results suggest that females may be more vulnerable than males to developing dependence after chronic cannabinoid exposure.

Effects of dehydroepiandrosterone in amphetamine-induced schizophrenia models in mice

OBJECTIVE

To examine the effects of dehydroepiandrosterone (DHEA) on animal models of schizophrenia.

METHODS

Seventy Swiss albino female mice (25-35 g) were divided into 4 groups: amphetamine-free (control), amphetamine, 50, and 100 mg/kg DHEA. The DHEA was administered intraperitoneally (ip) for 5 days. Amphetamine (3 mg/kg ip) induced hyper locomotion, apomorphine (1.5 mg/kg subcutaneously [sc]) induced climbing, and haloperidol (1.5 mg/kg sc) induced catalepsy tests were used as animal models of schizophrenia. The study was conducted at the Animal Experiment Laboratories, Department of Pharmacology, Medical School, Eskisehir Osmangazi University, Eskisehir, Turkey between March and May 2012. Statistical analysis was carried out using Kruskal-Wallis test for hyper locomotion, and one-way ANOVA for climbing and catalepsy tests.

RESULTS

In the amphetamine-induced locomotion test, there were significant increases in all movements compared with the amphetamine-free group. Both DHEA 50 mg/kg (p<0.05), and 100 mg/kg (p<0.01) significantly decreased all movements compared with the amphetamine-induced locomotion group. There was a significant difference between groups in the haloperidol-induced catalepsy test (p<0.05). There was no significant difference between groups in terms of total climbing time in the apomorphine-induced climbing test (p>0.05).

CONCLUSION

We observed that DHEA reduced locomotor activity and increased catalepsy at both doses, while it had no effect on climbing behavior. We suggest that DHEA displays typical neuroleptic-like effects, and may be used in the treatment of schizophrenia.

Evaluation of the antipsychotic potential of aqueous fraction of Securinega virosa root bark extract in mice

Securinega virosa (Roxb ex. Willd) Baill. is a plant which is commonly used in African traditional medicine in management of mental illness. Previous study showed that the crude methanolic root bark extract of the plant possesses antipsychotic activity. In this study, the antipsychotic potential of the residual aqueous fraction of the plant was evaluated using two experimental models, apomorphine induced stereotypic climbing behaviour and swim induced grooming, all in mice. The effect of the fraction on haloperidol-induced catalepsy was also evaluated. The fraction significantly reduced the mean climbing score at the highest dose tested (500 mg/kg). In the swim-induced grooming test, the fraction significantly and dose-dependently (125-500 mg/kg) decreased the mean number and mean duration of swim-induced grooming activity in mice. Similarly, the standard haloperidol (1 mg/kg) significantly (p < 0.001) decreased the mean grooming episodes and duration. However, the fraction did not significantly potentiate haloperidol-induced catalepsy. These results suggest that the residual aqueous fraction of methanol root bark extract of Securinega virosa contains biological active principle with antipsychotic potential.

The potency and efficacy of anticholinergics to inhibit haloperidol-induced catalepsy in rats correlates with their rank order of affinities for the muscarinic receptor subtypes

Extrapyramidal syndromes (EPS) caused by antipsychotic therapy are currently treated with anticholinergics that lack selectivity for the five muscarinic receptor subtypes. Since these receptors are heterogeneously expressed among the different classes of striatal neurons and their afferents, it can be expected that their simultaneous blockade will cause distinct, sometimes opposed, effects within the striatal circuitry. In order to test the hypothesis that the differential blockade of the muscarinic receptor subtypes would influence their potency and efficacy to prevent EPS, here we tested four anticholinergics with varying order of affinities for the muscarinic receptor subtypes, and compared their dose-response curves to inhibit haloperidol-induced catalepsy in male rats. Drugs were applied into the lateral ventricle 15 min before haloperidol (2 mg/kg, s.c.). Catalepsy was measured in the bar test at 15 min intervals during 5 h. The preferential M1/M4 antagonist pirenzepine (3, 10, 30, 100, and 300 nmol) caused a dose-dependent inhibition of catalepsy intensity: ED50 = 5.6 nmol [95% CI, 3.9-8.1], and latency: ED50 = 5.6 nmol [95% CI, 3.7-8.6]. Pirenzepine had the steepest dose-response curve, producing maximal inhibition (84 ± 5%) at the dose of 10 nmol, while its effect tended to reverse at higher doses (62 ± 11%). The purported M1/M3 antagonist 4-DAMP (30, 100, and 300 nmol) also caused a dose-dependent inhibition of catalepsy intensity: ED50 = 29.5 nmol [95% CI, 7.0 to 123.0], and latency: ED50 = 28.5 nmol [95% CI, 2.2 to 362.0]. However, the curve for 4-DAMP had a less pronounced slope, reaching its maximal effect (63 ± 14%) at the dose of 300 nmol. The M2/M4 antagonist AF-DX 116 (10, 30, and 300 nmol) only caused a partial inhibition of catalepsy (30 ± 11%) at the dose of 30 nmol, but this changed to a non-significant increment (15 ± 10%) at the dose of 100 nmol. The alleged M4 antagonist tropicamide (30, 100, 300, and 600 nmol) produced a partial inhibition of catalepsy (36 ± 12%) at the dose of 300 nmol, but lacked effect at higher or lower doses. Concurrent treatment with pirenzepine (10 nmol) and tropicamide (300 nmol) produced an effect similar to that of tropicamide alone. The greater potency and efficacy of pirenzepine for catalepsy inhibition could be due to its higher affinity for M1 receptors and, to a lesser extent, for M4 receptors. It is suggested that selective M1 antagonists would be more effective than M2, M3 or M4 antagonists to prevent EPS caused by antipsychotic drugs.

Dopamine-dependent behavior in adult rats after perinatal exposure to purity-controlled polychlorinated biphenyl congeners (PCB52 and PCB180)

Since knowledge about toxic effects of non-dioxinlike (NDL) PCBs is fragmentary, regulatory panels have concluded that risk assessment of these congeners is hampered or impossible. As the dopaminergic system is one of the main targets in PCB-related neurotoxic effects after developmental exposure, we selected catalepsy induced by the dopamine receptor blocker haloperidol to characterize effects of the NDL congeners PCB52 and PCB180 in adult offspring from exposed rat dams. Rat dams were treated with PCB congeners by gavage using six dose levels (total doses: PCB52 - 0, 30, 100, 300, 1000 or 3000 mg/kg body wt.; PCB180 - 0, 10, 30, 100, 300, or 1000 mg/kg body wt.) to allow benchmark dose analysis of the results. Testing of adult offspring (starting at 180 days of age) for catalepsy induced by injection with haloperidol revealed slightly prolonged latencies to movement onset in female offspring exposed to PCB52. Exposure to PCB180 resulted in more pronounced effects, with generally reduced latencies in male offspring. These results indicate reduced dopaminergic activity after PCB52 exposure, whereas the outcome for PCB180 may be related to increased extracellular dopamine as reported in the literature.Benchmark dose analyses revealed that both PCB congeners exerted effects mainly at moderate exposure levels. Together, these results underline the importance of effects on the dopaminergic system as indicated by studies in human females after occupational PCB exposure.

Anticataleptic effects of 5-HT(1B) receptors in the globus pallidus

The globus pallidus occupies an important position in the indirect pathway of the basal ganglia. Being a monoamine neurotransmitter, 5-HT is involved in mediating many physiological functions and pathophysiological processes in several movement disorders. Morphological studies have revealed that the globus pallidus receives serotonergic innervation arising from the raphe nuclei, mainly the dorsal raphe nucleus. A high level of 5-HT and 5-HT(1B) receptors were detected in the globus pallidus. In the present study, bilateral microinjection of 5-HT or 5-HT(1B) receptor agonist, CP-93129, into the globus pallidus significantly alleviated the symptoms of rigidity caused by haloperidol. To further elucidate 5-HT(1B) receptor-induced anticatalepsy, in vivo extracellular recordings were performed to examine the effects of 5-HT(1B) receptor activation on the firing activity of the globus pallidus neurons under the presence of haloperidol. Micro-pressure ejection of 5-HT or CP-93129 increased the spontaneous firing rate of the pallidal neurons. Furthermore, by using immunohistochemistry, positive staining of 5-HT(1B) receptor was observed in the globus pallidus neurons. Taken together, the present findings provide evidence that activation of 5-HT(1B) receptor may exert anticataleptic effects by increasing the activity of pallidal neurons.

Pharmacological and genetic evidence for pre- and postsynaptic D2 receptor involvement in motor responses to nociceptin/orphanin FQ receptor ligands

A combined pharmacological and genetic approach was undertaken to investigate the contribution of endogenous dopamine to the motor actions of nociceptin/orphanin FQ (N/OFQ) receptor (NOP receptor) ligands. Motor activity was evaluated by a battery of behavioural tests in mice. The involvement of the various DA receptor subtypes in the motor effects of N/OFQ and NOP receptor antagonists was evaluated pharmacologically, using D1/D5 (SCH23390), D2/D3 (raclopride, amisulpride) and D3 (S33084) receptor antagonists, and by using D2 receptor knockout mice. Low doses of N/OFQ and NOP receptor antagonists promoted movement whereas higher doses inhibited it. Motor facilitation was selectively prevented by raclopride while motor inhibition was prevented by amisulpride. Amisulpride also attenuated the hypolocomotion induced by the D2/D3 receptor agonist pramipexole and dopamine precursor l-3,4-dihydroxyphenylalanine, whereas raclopride (and S33084) worsened it. To dissect out the contribution of pre- and postsynaptic D2 receptors, mice lacking the D2 receptor (D2R(-/-)) or its long isoform (D2L(-/-)) were used. Motor facilitation induced by N/OFQ and NOP receptor antagonists was lost in D2R(-/-) and D2L(-/-) mice whereas motor inhibition induced by NOP receptor antagonists (and pramipexole) was lost in D2R(-/-) but preserved in D2L(-/-) mice. N/OFQ-induced hypolocomotion was observed in both genotypes. We demonstrate that motor actions of NOP receptor ligands rely on the modulation of endogenous dopamine. Motor facilitation induced by NOP receptor antagonists as well as low dose N/OFQ is mediated through D2L postsynaptic receptors whereas motor inhibition observed with higher doses of N/OFQ occurs by direct inhibition of mesencephalic DA neurons. Motor inhibition seen with high doses of NOP receptor antagonists appears to be mediated through the D2 presynaptic autoreceptors. These data confirm that endogenous N/OFQ is a powerful modulator of dopamine transmission in vivo and that the effects of NOP receptor antagonists on motor function reflect the blockade of this endogenous N/OFQ tone.

Aqueous ethanol extract of the fruit of Xylopia aethiopica (Annonaceae) exhibits anti-anaphylactic and anti-inflammatory actions in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Xylopia aethiopica has been traditionally used in the form of the dried fruit decoction to treat bronchitis, asthma, arthritis and rheumatism in Ghana, Nigeria and Cameroon. Aim of the study is to evaluate the anti-anaphylactic and anti-inflammatory effects of a 70% aqueous ethanol extract of the fruits of Xylopia aethiopica.

MATERIALS AND METHODS

Systemic anaphylaxis was induced by the injection of either compound 48/80 or lipopolysaccharide, LPS and survival rates of mice monitored for 1 h or 7 days respectively while IgE-mediated anaphylaxis in a local allergic reaction was studied in the pinnal inflammation model in mice. Clonidine-induced catalepsy in mice was used to evaluate the indirect antihistamine effect of Xylopia aethiopica, XAE. The effects of XAE assessed on the maximal and total oedema responses in the carrageenan-induced paw oedema in mice was used to evaluate the anti-inflammatory action of the extract.

RESULTS

Administered at 30, 100, 300 and 1000 mg kg(-1) p.o., XAE dose dependently suppressed compound 48/80-induced mouse systemic anaphylactic shock and offered 63% protection to mice against LPS-induced endotoxic shock at a dose of 300 mg kg(-1). In addition, the extract (30-300 mg kg(-1)) in a dose dependent manner significantly inhibited by 23-62% the mouse pinnal inflammation. Clonidine-induced catalepsy in mice was significantly suppressed in a dose and time dependent manner when administered both prophylactically and therapeutically. In the same doses, when administered before the induction of the mouse carrageenan-induced paw oedema, the mean maximal swelling attained during 6 h was reduced to 41.02±6.94%, 35.61±4.30%, and 29.09±4.90% of the inflamed control response respectively and total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed to 74.84±14.84%, 63.95±9.37%, and 48.13±10.90% of the inflamed control response respectively. Administered after the induction of the carrageenan paw oedema the mean maximal swelling attained during 6 h was suppressed to 49.84±3.95%, 43.62±1.01%, and 35.97±1.34% of the inflamed control response respectively while the total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed at 100 and 300 mg kg(-1) to 72.39±4.38% and 60.81±3.25% of the inflamed control response respectively.

CONCLUSION

These findings suggest that XAE inhibits mast cell-dependent immediate allergic reactions and exhibit anti-inflammatory actions through the inhibition of histamine release from mast cells via stabilizing the cell membrane. Our results contribute towards validation of the traditional use of Xylopia aethiopica in the treatment of bronchitis, asthma, arthritis and rheumatism.

A2A receptor antagonists do not induce dyskinesias in drug-naive or L-dopa sensitized rats

L-dopa, the precursor to dopamine, is currently the gold standard treatment for Parkinson's disease (PD). However, chronic exposure is associated with L-dopa-induced dyskinesias (LIDs), a serious side effect characterized by involuntary movements. Adenosine A2A receptor antagonists have been studied as a novel non-dopaminergic PD treatment. Because A2A receptor antagonists do not act on dopamine receptors, it has been hypothesized that they will not induce dyskinesias characteristic of L-dopa. To test this hypothesis in a rodent model, the A2A receptor antagonists SCH 412348 (3 mg/kg), vipadenant (10 mg/kg), caffeine (30 mg/kg), or istradefylline (3 mg/kg) were chronically (19-22 days) administered to Sprague Dawley rats, and dyskinetic behaviors were scored across this chronic dosing paradigm. Unlike L-dopa, there was no evidence of dyskinetic activity resulting from any of the four A2A receptor antagonists tested. When delivered to animals previously sensitized with L-dopa (6 mg/kg), SCH 412348, vipadenant, caffeine or istradefylline treatment produced no dyskinesias. When administered in combination with L-dopa (6 mg/kg), SCH 412348 (3 mg/kg) neither exacerbated nor prevented the induction of LIDs over the course of 19 days of treatment. Collectively, our data indicate that A2A receptor antagonists are likely to have a reduced dyskinetic liability relative to L-dopa but do not block dyskinesias when coadministered with L-dopa. Clinical studies are required to fully understand the dyskinesia profiles of A2A receptor antagonists.

Differential network analysis reveals genetic effects on catalepsy modules

We performed short-term bi-directional selective breeding for haloperidol-induced catalepsy, starting from three mouse populations of increasingly complex genetic structure: an F₂ intercross, a heterogeneous stock (HS) formed by crossing four inbred strains (HS4) and a heterogeneous stock (HS-CC) formed from the inbred strain founders of the Collaborative Cross (CC). All three selections were successful, with large differences in haloperidol response emerging within three generations. Using a custom differential network analysis procedure, we found that gene coexpression patterns changed significantly; importantly, a number of these changes were concordant across genetic backgrounds. In contrast, absolute gene-expression changes were modest and not concordant across genetic backgrounds, in spite of the large and similar phenotypic differences. By inferring strain contributions from the parental lines, we are able to identify significant differences in allelic content between the selected lines concurrent with large changes in transcript connectivity. Importantly, this observation implies that genetic polymorphisms can affect transcript and module connectivity without large changes in absolute expression levels. We conclude that, in this case, selective breeding acts at the subnetwork level, with the same modules but not the same transcripts affected across the three selections.

Role of L-thyroxin in counteracting rotenone induced neurotoxicity in rats

A key feature of Parkinson's disease is the dopaminergic neuronal cell loss in the substantia nigra pars compacta. Many triggering pathways have been incriminated in the pathogenesis of this disease including inflammation, oxidative stress, excitotoxicity and apoptosis. Thyroid hormone is an essential agent for the growth and maturation of neurons; moreover, it has variable mechanisms for neuroprotection. So, we tested the efficacy of (L)-thyroxin as a neuroprotectant in rotenone model of Parkinson's disease in rats. Thirty Sprague Dawley rats aged 3 months were divided into 3 equal groups. The first received daily intraperitoneal injections of 0.5% carboxymethyl cellulose (CMC) 3 mL/Kg. The second group received rotenone suspended in 0.5% CMC intraperitoneally at a dose of 3 mg/kg, daily. The third group received the same rotenone regimen subcutaneous l-thyroxine at a dose of 7.5 μg daily. All animals were evaluated regarding locomotor disturbance through blinded investigator who monitored akinesia, catalepsy, tremors and performance in open field test. After 35 days the animals were sacrificed and their brains were immunostained against anti-tyrosine hydroxylase and iba-1. Photomicrographs for coronal sections of the substantia nigra and striatum were taken and analyzed using image J software to evaluate cell count in SNpc and striatal fibers density and number of microglia in the nigrostriatal system. The results were then analyzed statistically. Results showed selective protective effects of thyroxin against rotenone induced neurotoxicity in striatum, however, failed to exert similar protection on SN. Moreover, microglial elevated number in nigrostriatal system that was induced by rotenone injections was diminished selectively in striatum only in the l-thyroxin treated group. One of the possible mechanisms deduced from this work was the selective regulation of microglia in striatal tissues. Thus, this study provides an insight into thyroxin neuroprotection warranting further investigation as therapeutic option for Parkinson's disease patients.

Caffeine has greater potency and efficacy than theophylline to reverse the motor impairment caused by chronic but not acute interruption of striatal dopaminergic transmission in rats

In order to assess whether caffeine and theophylline have the same potency and efficacy to reverse the impairment of motor function caused by acute or chronic interruption of striatal dopamine transmission, a comparison of their dose-response relationship was made in the acute model of haloperidol-induced catalepsy, and the chronic model of unilateral lesion of the dopamine nigrostriatal pathway with 6-hydroxydopamine. At equimolar doses, both drugs reduced catalepsy intensity and increased its onset latency in a dose-dependent fashion, showing comparable potencies and attaining the maximal effect at similar doses. Catalepsy intensity: caffeine ED₅₀ = 24.1 μmol/kg [95% CI, 18.4-31.5]; theophylline ED₅₀ = 22.0 μmol/kg [95% CI, 17.0-28.4]. Catalepsy latency: caffeine ED₅₀ = 27.0 μmol/kg [95% CI, 21.1-34.6]; theophylline ED₅₀ = 28.8 μmol/kg [95% CI, 22.5-36.7]. In one group of hemiparkinsonian rats (n = 5), caffeine caused a dose-dependent recovery of the contralateral forepaw stepping: ED₅₀ = 2.4 μmol/kg/day [95% CI, 1.9-3.1]), reaching its maximum at the dose of 5.15 μmol/kg/day. When the treatment of these same rats was switched to 5.15 μmol/kg/day of theophylline, the stepping recovery was only 51 ± 12% of that induced by caffeine. Assessing the dose-response relationship of theophylline in another group of hemiparkinsonian rats (n = 7) revealed that it caused stepping recovery in an all-or-none fashion. Thus, the three lower doses had no effect, but at the dose of 5.15 μmol/kg/day theophylline suddenly increased the stepping to 56 ± 5% of the maximal effect observed when the treatment of these same rats was switched to an equimolar dose of caffeine. Increasing the dose of theophylline up to 15.45 μmol/kg/day caused no further stepping improvement since it was only 41 ± 6% of the maximal effect produced by caffeine at the dose of 5.15 μmol/kg/day. Given that theophylline showed less potency and efficacy than caffeine to reverse the motor impairment caused by chronic, but not acute, interruption of striatal dopaminergic transmission in rats, it is suggested that caffeine would provide more benefits than theophylline to improve the motor function in patients with Parkinson's disease.

Individual phenotype predicts nicotine-haloperidol interaction in catalepsy: possible implication for the therapeutic efficacy of nicotine in Tourette's syndrome

In individuals with Tourette's syndrome, the therapeutic efficacy of haloperidol can be augmented by nicotine. In laboratory rats, the dopamine antagonist haloperidol produces catalepsy and nicotine can potentiate it, although this effect is variable and not always observed. Our aim was to understand this variability. In rats, the locomotor response to a novel environment predicts the magnitude of the locomotor response to nicotine. Since the psychostimulant effect of nicotine might counter catalepsy, we hypothesized that rats with a high locomotor response to novelty would show reduced vulnerability to nicotine potentiation of haloperidol catalepsy. First, we administered haloperidol (0, 0.1 or 0.3mg/kg, ip) and found stronger catalepsy in rats with low reactivity to novelty. Second, we administered haloperidol (0.3mg/kg) or haloperidol plus nicotine (0.1mg/kg, ip) and found that nicotine indeed potentiated haloperidol catalepsy but only in rats with low reactivity to novelty. Nicotine did not induce catalepsy on its own. Thus, previously reported inconsistencies in the catalepsy potentiating effect of nicotine may have been due to differential vulnerability to its stimulant actions. As previously observed, the potentiation of haloperidol catalepsy was greatest 4h after injection. Given the short half-life of nicotine, the mechanism(s) underlying the delayed expression of its pro-cataleptic capacity remains obscure.

[On filo- and ontogenetic development of dopaminergic regylation of wakefulness-sleep cycle in vertabrates]

The comparative immunohistochemical researches of dofamine containing neurons and fibers are carried uot in telencephalic and diencephalic departments of the brain in different vertebratts (adults rats, rats aged 14 and 30 days and frogs). For analysis of quantitative changes dynamics in thyrozinhydroxylase, D1 and D2 immunoreactive material in sleep-wakefulness cycle the model of sleepdeprivation is used. There are found the facts of morphofunctional correlations in the reactions of dophaminergic system during ontogeny and phylogeny. Besides, the pharmacological effects of dofamine agonist and antagonists on the sleep-wakefulness cycle in young rats and in frogs are shown. So, dopamine and its agonist apomorphine increase in sleep-wakefulness cycle duration of sleep-like state ofcataplexy (homolog of the sleep) in frogs, in 30-day-old rats it increase the share of wakefulness and catalepsy. D1 receptors antagonist (SCH 23390) adminisrated to frogs, caused increase of wakefulness and catatonic type states duration, where as D2 receptors antagonist (apomorphine) increased cataleptic condition. Administration of dopamine antagonist (haloperidol) to 30-day-old rats previously causes the increase of cataleptic state, after which the slow wave sleep state is enhanced. The questions of phylo-, ontogenetic formation of dopaminergic system regulating role in sleep-wakefulness cycle, when transition mainly from neurosecretory diencephalic influences of dophamine to the mainly neurotransmittory functins of telencephalic regions occured, is discussed.

Regenerative effects of umbilical cord matrix cells (UCMCs) in a rodent model of rotenone neurotoxicity

Rotenone is one of the pesticides thought to have neurotoxic effect that could potentially play a role in the development of Parkinson's disease (PD). The neurotoxic effects of rotenone have been used to induce PD model in animals that can help in testing suggested therapies. Cell replacement therapies are suggested as new promising approach for treating PD. This study was done to evaluate the regenerative effect of intrathecal administered umbilical cord matrix cells in a rotenone model of PD in mice. Thirty, male BALB/c mice were used and divided into 3 equal groups. The control group (G.1) received only carboxymethyl cellulose orally once daily at a volume of 10ml/kg. The second group was given a daily rotenone oral dose of 30mg/kg for 28days. The third group received rotenone (30mg/(kgday) orally for 28days) and in the 15th day 1×10(5) of UCMCs were given intrathecally and then they completed the rotenone course. At the 23rd day all the animals were evaluated regarding locomotor incoordination through behavioral tests for monitoring PD development. At the end of the 28days all animals were sacrificed by overdose of phenobarbital and their brain were subjected to immunohistochemical analysis for dopaminergic neurons staining for anti TH antibodies. Intrathecal UCMCs revealed regenerative effects in SNpc as evidenced by immunohistochemical staining; this was in parallel with better performance in behavioral tests. In conclusion, the results of this study revealed the regenerative capacities of UCMCs against rotenone neurotoxicity in mice.

Antihistaminic and antiallergic actions of extracts of Solanum nigrum berries: possible role in the treatment of asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Berries of the plant Solanum nigrum Linn (Solanaceae) are used for the treatment of asthma in folk medicine and ancient books.

AIM OF STUDY

To evaluate potential of the plant berries in the treatment of asthma.

MATERIALS AND METHODS

Petroleum ether, ethanol and aqueous extracts of S. nigrum berries (50, 100 and 200mg/kg, i.p.) were screened for the treatment of asthma by the various methods viz. effect on clonidine and haloperidol induced catalepsy, milk-induced leucocytosis and eosinophilia, mast cell stabilizing activity in mice and studies on smooth muscle preparation of guinea pig ileum (in vitro). Active petroleum ether extract was standardized by HPTLC.

RESULTS

The petroleum ether extract of S. nigrum berries inhibited clonidine-induced catalepsy significantly but not haloperidol-induced catalepsy. Petroleum ether extract significantly inhibited increased leukocyte and eosinophil count due to milk allergen and showed maximum protection against mast cell degranulation by clonidine. Petroleum ether extract resisted contraction induced by histamine better than other extracts. All the results are dose dependant. Active petroleum ether extract showed presence of antiasthmatic compound, β-sitosterol.

CONCLUSION

The petroleum ether extract of S. nigrum berries can inhibits parameters linked to the asthma disease.

Sedative, antiepileptic and antipsychotic effects of Viscum album L. (Loranthaceae) in mice and rats

ETHNOPHARMACOLOGICAL RELEVANCE

Viscum album L. is claimed in traditional medical practice, to be useful in the treatment of epilepsy and insomnia in Himachal Pradesh, India.

MATERIALS AND METHODS

The effect of Viscum album L. on epilepsy, psychosis and sedative activity was evaluated in mice and rats using standard procedure.

RESULTS

The aqueous leaf extract of Viscum album L. prolonged the pentobarbital induced sleeping time and reduced the locomotor activity in actophotometer. This suggests that reduced locomotor activity facilitate GABAergic transmission. In addition the extract reduced MES, INH and PTZ-induced convulsions which suggest that there may be possibility of blocking Na(+) channels, opening of Cl(-) channels or enhancing the GABAergic system. The extract decreased the apomorphine-induced stereotyped behavior and potentiates the HAL-induced cataleptic score which suggests the extract possess antidopaminergic activity.

CONCLUSION

The results obtained in present study suggested that title plant exhibited sedative, antiepileptic and antipsychotic activity in mice and rats.