The pruritogenic effect of Anaphe venata extracts in rats: the role of cholinergic, GABAergic and opioid systems

This study sought to investigate the effect of the crude aqueous and phosphate buffer saline (PBS) extracts of Anaphe venata on body scratching behaviour in rat in a novel environment and also to determine the neural mechanism(s) involved. Aqueous and PBS extracts of Anaphe venata were prepared and their effects on body scratching behaviour were evaluated in rats. Animals were divided into four groups (n = 6-12 per group) and graded doses of extracts (100-400 mg/kg) were administered (dissolved in normal saline) intraperitoneally (i.p.) to each animal in the experimental groups. The control group received an equivalent volume of normal saline. Behavioural scores were recorded for a period of 30 minutes after the administration of normal saline or extract. The role of various receptors in the extract induced pruritus was evaluated using known receptor agonist/antagonists. Results showed that aqueous Anaphe extract induced dose-dependent increase in body scratching behaviour (

Neuropharmacological effects of Alchornea cordifolia (Schumach. & Thonn.) Mull. Arg. (Euphorbiaceae) in mice

Alchornea cordifolia (Euphorbiaceae) is a common plant, which has featured prominently in traditional medicinal practice. It has been reported that the decoction of the leaves is taken as central nervous system stimulant. This work was therefore undertaken to examine the central nervous system effects. The neuropharmacological profile of the plant was determined in mice to which the plant extract had been orally administered at respective doses of 250, 500 and 1,000 mg/kg. The behavioral models used included noveltyinduced behaviors (locomotion, rearing and grooming), holeboard and elevated plus maze (anxiolytic) and forced swimming (antidepressant). The Y-maze was used for the investigation of the plant extract on locomotion, learning and memory. The results obtained showed that both locomotor and rearing activities were significantly decreased at the highest dose of 1000 mg/kg orally, while grooming behavior was significantly decreased at all the doses administered. In the hole board experiment, the frequency of head-dips was decreased significantly at 1000 mg/kg, while there was no significant effect observed in the elevated plus maze. Y-maze model results showed that it had no significant effect on spatial memory. There was no significant difference in the immobility duration due to administration of the extract in the forced swimming test. In conclusion, the present study showed that although the ethanolic leaf extract of A. cordifolia exhibited some central inhibitory effect, it is devoid of anxiolytic, antidepressant activities and has no significant effect on learning and memory in mice.Keyword: A. cordifolia, locomotion, grooming, mice, anxiolytic, antidepressant, mic

Reducing the barriers to the uptake of cataract surgical services in a tertiary hospital

Background: Cataract is a major cause of avoidable blindness and isresponsible for about 50% of global blindness.Objective: To determine the effect of reducing barriers to the uptake of cataract surgical services at the University of Benin Teaching Hospital, Benin City, Nigeria.Study Design and Methods: A comparative retrospective study of the number of cataract surgeries performed from January 2005 to December 2008 was carried out. A joint partnership between the Ophthalmology Department, the hospital management and a non-profit, non-governmental organization (NGO) was established to tackle the barriers of awareness, access and high cost of surgery to the uptake of cataract surgery from January 2005. The Ophthalmology Department and hospital management agreed to perform cataract surgeries free for all cataract patients while the NGO provided all the consumables required. The number of cataract surgeries performed was obtained from the theatre records and the data obtained analysed for the number of surgeries done per year.Results: The total number of cataract surgeries performed as seventy five (75), one hundred and twenty nine (129), one hundred and six (106) and three hundred and eighty-three (383) for the years 2005, 2006, 2007 and 2008, respectively showing a significant increase in the year 2008. Poor awareness, the bureaucracy of the referral system and high cost of surgery were identified as barriers to the uptake of cataract surgical services at the University of Benin Teaching Hospital. Publicity through the mass media, direct presentation of patients to the eye clinic for screening and providing cataract services free to all patients were methods used to overcome these barriers. Conclusion: Cataract surgical output can be increased by concerted effort and joint partnership among stakeholders in the eye care sector by recognising and reducing the barriers to the uptake of cataract surgical services.Keywords: barriers, cataract, surgical services, tertiary hospita

Studies on the Anxiolytic Effect of Spondias mombin l. (Anacardiaceae) Extracts

Spondias mombin L [Anacardiaceae] is a plant used by traditional medical practitioners in Nigeria in the treatment of various nervous disorders. In this study, the anxiolytic properties of the aqueous, methanol and ethanol extracts of the leaves were examined using aggressivebehaviour response and depression-related swimming behaviour activities. All the extracts administered orally were not toxic to mice up to a dose of 5 g/kg. On intraperitoneal injection, however, the LD50 values [mice/rats] were calculated to be 0.48 g/kg / 0.62 g/kg for ethanol extract, 1.10 g/kg / 1.08 g/kg for methanol extract and 1.36 g/kg / 1.42 g/kg for aqueous extract respectively. All residues from different extractions were dissolved in normal saline and administered intraperitoneally. It was found that the three extracts abolished the aggressive attacks by rats, and reduced swimming time in mice. These effects were found to be most potent with the administration of the ethanol extract. These effects of the extracts were blocked by flumazenil, an antagonist of GABAA receptor. The results suggest that the extracts of Spondias mombin possess anxiolytic effect mediated by GABAergic transmission. Key Words: Spondias mombin, neurological, muricidal, swimming despair, GABA receptor antagonist. Afr. J. Trad. CAM (2005) 2 (2): 153-16

Malaria Parasite Infection and Chloroquine-Induced Pruritus: The Role of Opioid-Peptides

Pruritus or itch is associated with malaria infection and/or chloroquine chemotherapy. This study examined the relationship between parasitaemia and chloroquine (CQ) on body scratching (BS) in healthy (un-infected) and malaria-infected rats. The malaria parasite induced a significant (p< 0.001) increase in body scratching (28.3 ± 4.6) compared to un-infected rats (7.7 ± 1.0). Intraperitoneal administration of CQ (20 mg/kg, i.p) increased the frequency of body scratching (28.7 ± 8.1) compared to control animals (7.5 ± 1.0, p < 0.001). The &#61549;-opioid receptor antagonist, naltrexone (0.25mg/kg i.p given 15 minutes prior) blocked both parasite and CQ (20mg/kg)–induced body scratching. In morphine tolerant rats, the frequency of BS was significantly reduced (12.7 ± 3.7,

Acute toxicity and sleep-wake EEG analysis of Stachtarpheta cayennensis (Verbenaceae) in rodents

This study was carried out in order to establish the scientific basis of the reported ethno-medicinal use of Stachytarpheta cayennensis (Verbanaceae) as sedative drug. The acute toxicity and barbituric-hypnotic test of the total aqueous (TASC), 50% ethanol (SCCR) and butanol (SCBT), ethylacetate (SCEA) fractions of dried leaves of S. cayennensis were studied in male rats and mice. The effect of systemic administration of TASC on sleep architecture in rats was also evaluated in Sprague-Dawley rats that were chronically implanted with electrodes for electroencephalogram (EEG) and electromyogram (EMG) recording. The acute toxicity test revealed no lethal effect with doses of SCCR (up to 2000 mg/kg) per oral in rats and doses of TASC (up to 1000 mg/kg and 95 mg/kg) systemically in rats and mice respectively. The extracts significantly (p < 0.01) potentiated phenobarbital-induced hypnosis by reducing sleep latency and increasing sleeping time in a dose-dependent manner. Systemic nocturnal administration of single doses (250 and 500 mg/kg) 30 minutes before the onset of dark period of TASC significantly (p < 0.05) increased total sleep time, time spent in non-rapid eye movement (NREM) sleep during the 6-h recording period while its effect on REM sleep was biphasic with the higher dose administered. The aqueous extract of Stachytarpheta cayennensis showed profound effects on sleep-wake stages suggesting the potential sedative effects. Key words: Stachytarpheta cayennensis, acute toxicity, barbituric-hypnotic test, Wake, NREM sleep, REM sleep Afr. J. Trad. Comp. Alt. Med. Vol.2(3) 2005: 222 - 23

Involvement of cholinergic-muscarinic receptor in Anaphe venata-induced stretching-ataxia behavioral effects in rats

Anaphe venata entomophagy has previously been implicated in the aetiopathogenesis of seasonal ataxia in humans and altered motor function in rodents. Thus, we investigated the effect of A. venata PhosphateBuffer Saline (PBS) extract on stretching, ataxia and the possible mechanism(s) of action. Animals were divided into four groups (n = 6-12 per group) and graded doses of extract (100, 200 or 400 mg/kg) wereadministered intraperitoneally (i.p.) while the control group received saline. Behavioral scores were recorded for a period of 30 min immediately after the administration of saline or extract. The role of various receptors inthe extract induced stretching and ataxia was evaluated using known receptor antagonists in other groups of rats. The in-vitro cholinesterase inhibition assay of the extract was also performed. The protein profile of theextract was evaluated using the Sodium Dodecyl Sulphate&nbsp; (SDS)-Polyacrylamide gel electrophoresis. Results showed that the extract induced significant (p&lt;0.01) stretching and ataxia behavioural effects dose-dependently when compared to vehicle-treated rats. Pretreatment with the non-selective muscarinic antagonist, scopolamine, significantly (p&lt;0.05) reversed both stretching and ataxia-induced behaviour of PBS extract at alldose levels however both flumazenil and naloxone did not show any significant effects. Anticholinesterase assay also provided evidence that the extract has inhibitory effect on acetylcholinesterase enzyme. Electrophoresis assay suggested that the major proteins in the extract are probably of small molecular weight. In conclusion, the A. venata PBS extract induced-behaviours are probably mediated via the activation of cholinergic-muscarinic receptor systems

Neuropharmacological Evaluation of Aridanin, a Glycoside Isolated from Tetrapleura tetraptera Fruit

The neuropharmacological effects of Aridanin Ð an N-acetylated glycoside isolated from Tetrapleura tetraptera fruit was examined for locomotory, exploratory, stereotyped behaviours and hexobarbitone-induced sleeping time (HIST) in mice. Aridanin (15- and 30 mg/kg i.p) produced a dose-dependent inhibition of novelty-induced rearing, grooming, body scratching and exploratory behaviour. It also potentiated the hexobarbitone-induced sleeping time (HIST), but did not change the stereotyped behaviour induced by apomorphine. These effects of aridanin suggest that it has a strong central depressant action which may be sedative in nature but lack psychopharmacological activities Keywords: Aridanin; central activities, sedation, Tetrapleura tetraptera fruitDiscovery and Innovation Vol. 19 (3) 2007: pp. 177-18

Effect of Extracts and Isolated Pure Compounds of Spondias Mombin (l. Anacardiaceae) Leaves on Gross Exploratory Behaviors in Mice.

Previous studies have reported several neuro-physiological effects of crude extracts of Spondias mombin leaves, which is widely used by traditional medical practitioners in Nigeria for the treatment of neuro-psychiatric disorders. However the neuro-physiological effects of fractionated extracts and pure isolates, with the pharmacological mechanisms responsible for these effects have remained largely unexplored. This study elucidated the neurotransmitter systems and receptors involved in the effects of extracts, and isolated compounds of Spondias mombin leaves in mice (n = 5 - 6) after intraperitoneal (i.p.) route of administration on gross explorative behaviors in mice. The crude ethanolic extract of Spondias mombin leaves was fractionated using the partitioning method to obtain the ethylacetate, butanolic and aqueous fractions. Open column chromatographic fractionation of the ethylacetate fraction yielded seven sub-fractions, out of which the pure coumaroyl, quercetin and gallic acid derivatives were obtained after purification on Sephadex LH-20. The ethanolic extract, butanolic, ethylacetate fractions, ethylacetate subfractions and pure isolates of the Spondias mombin leaves were tested on open field locomotion and head dipping behaviors in mice using standard pharmacological tools. The results showed that the ethanolic and butanolic extracts decreased open field locomotion, while ethylacetate fraction increased open field locomotion at lower doses, but decreased it at higher  doses. Subfractions S1 - S7 decreased open field locomotion except S2 ,which had no effect on open field locomotion. The three pure isolates decreased open field locomotion. Pre-treatment with yohimbine, atropine and propranolol had no effect on the coumaroyl derivatibe-induced effect on open field behavior, naloxone reversed this effect while haloperidol potentiated the inhibitory effects of the three pure isolates on open field locomotion. Ethanolic and butanolic decreased head dipping behavior in a dose dependent manner, while ethylacetate fraction increased head dips at lower doses, but decreased it at higher doses. Subfractions S1 - S7 decreased the number of head dips except S2, which had no effect. Coumaroyl derivative had no effect, but gallic acid and quercetin derivatives decreased the number of head dips. Yohimbine, atropine, propranolol and haloperidol potentiated the inhibitory effect of gallic acid and quercetin derivatives on head dips, whereas naloxone reversed the effect of coumaroyl and quercetin derivatives on head dips. It can be inferred that blockade of opioid receptors consistently reversed the effect of coumaroyl derivative on open field locomotion and head dipping behaviors, while blockade of dopaminergic receptors consistently facilitated the effects of the three pure isolates on open field locomotion and head dipping behaviors. It is suggested that the opioid and dopaminergic neurotransmitter systems are strongly involved in the behavioral effects of pure isolates of Spondias mombin leaves in mice.Keywords : Receptors; Neurotransmitters; Explorative Behaviors; Coumaroyl, Gallic Acid; Quercertine; Spondias mombin

Acute and Sub-Chronic Toxicity Potential Effects of Alchornea Cordifolia (Euphorbiaceae) in Rats

Alchornea cordifolia (Euphorbiaceae) is a plant that has been shown to have considerable activity against a broad spectrum of bacteria including those that have developed resistance to several antibiotics. In view of the high prevalence of antibiotic resistant bacteria, the search for new effective antimicrobial substances is urgent and must be extended to higher plants such as A. cordifolia. A useful antimicrobial substance must however have a defined toxicity profile which is why this attempt was thought to be worthy of serious consideration. Both oral acute and sub-chronic toxicity studies were carried out in rats. Acute toxicity study revealed that the ethanolic extract has no significant effect on both Packed cell volume (PCV) and Hemoglobin (Hb) and biochemical parameters. Similarly, the sub-chronic administration had no significant effect on hematological parameters and biochemical parameters such as protein, total cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutathione (GSH), however, triglyceride (TG) and lactate dehydrogenase (LDH) were significantly increased at the dose of 250 mg/kg/day when compared with the vehicle-treated rats. Furthermore, there was a significant increase in protein, TG and LDH at the dose of 500 mg/kg/day when compared with the dose of 250 mg/kg/day. Histopathological results revealed that there were no significant changes in the organs of the treated animals when compared with vehicle-treated group. The open field test showed that sub-chronic administration increased rearing behavior significantly at the dose of 250 mg/kg/28 days but had no effect on grooming. In conclusion, the ethanolic extract has no toxicological effect as observed on hematological, biochemical and histopathological parameters even at the maximum dose administered suggesting that the plant ethanolic leaf extract is devoid of any toxicity effects