Cannabidiol modulates excitatory-inhibitory ratio to counter hippocampal hyperactivity.

Cannabidiol (CBD), a non-euphoric component of cannabis, reduces seizures in multiple forms of pediatric epilepsies, but the mechanism(s) of anti-seizure action remain unclear. In one leading model, CBD acts at glutamatergic axon terminals, blocking the pro-excitatory actions of an endogenous membrane phospholipid, lysophosphatidylinositol (LPI), at the G-protein-coupled receptor GPR55. However, the impact of LPI-GPR55 signaling at inhibitory synapses and in epileptogenesis remains underexplored. We found that LPI transiently increased hippocampal CA3-CA1 excitatory presynaptic release probability and evoked synaptic strength in WT mice, while attenuating inhibitory postsynaptic strength by decreasing GABAARγ2 and gephyrin puncta. LPI effects at excitatory and inhibitory synapses were eliminated by CBD pre-treatment and absent after GPR55 deletion. Acute pentylenetrazole-induced seizures elevated GPR55 and LPI levels, and chronic lithium-pilocarpine-induced epileptogenesis potentiated LPI's pro-excitatory effects. We propose that CBD exerts potential anti-seizure effects by blocking LPI's synaptic effects and dampening hyperexcitability.

IQGAP1 promotes chronic pain by regulating the trafficking and sensitization of TRPA1 channels.

TRPA1 channels have been implicated in mechanical and cold hypersensitivity in chronic pain. But how TRPA1 mediates this process is unclear. Here we show that IQ motif containing GTPase activating protein 1 is responsible using a combination of biochemical, molecular, Ca2+ imaging and behavioural approaches. TRPA1 and IQ motif containing GTPase activating protein 1 bind to each other and are highly colocalized in sensory dorsal root ganglia neurons in mice. The expression of IQ motif containing GTPase activating protein 1 but not TRPA1 is increased in chronic inflammatory and neuropathic pain. However, TRPA1 undergoes increased trafficking to the membrane of dorsal root ganglia neurons catalysed by the small GTPase Cdc42 associated with IQ motif containing GTPase activating protein 1, leading to functional sensitization of the channel. Activation of protein kinase A is also sufficient to evoke TRPA1 trafficking and sensitization. All these responses are, however, completely prevented in the absence of IQ motif containing GTPase activating protein 1. Concordantly, deletion of IQ motif containing GTPase activating protein 1 markedly reduces mechanical and cold hypersensitivity in chronic inflammatory and neuropathic pain in mice. IQ motif containing GTPase activating protein 1 thus promotes chronic pain by coupling the trafficking and signalling machineries to TRPA1 channels.

Pro-opiomelanocortin neurons in the nucleus of the solitary tract mediate endorphinergic endogenous analgesia in mice.

ABSTRACT: The nucleus of the solitary tract (NTS) contains pro-opiomelanocortin (POMC) neurons that are 1 of the 2 major sources of ß-endorphin in the brain. The functional role of these NTS POMC neurons in nociceptive and cardiorespiratory function is debated. We have shown that NTS POMC optogenetic activation produces bradycardia and transient apnoea in a working heart-brainstem preparation and chemogenetic activation with an engineered ion channel (PSAM) produced opioidergic analgesia in vivo. To better define the role of the NTS POMC neurons in behaving animals, we adopted in vivo optogenetics (ChrimsonR) and excitatory/inhibitory chemogenetic DREADD (hM3Dq/hM4Di) strategies in POMC-Cre mice. We show that optogenetic activation of NTS POMC neurons produces time-locked, graded, transient bradycardia and bradypnoea in anaesthetised mice that is naloxone sensitive (1 mg/kg, i.p.), suggesting a role of ß-endorphin. Both optogenetic and chemogenetic activation of NTS POMC neurons produces sustained thermal analgesia in behaving mice that can be blocked by naloxone. It also produced analgesia in an inflammatory pain model (carrageenan) but not in a neuropathic pain model (tibial nerve transection). Inhibiting NTS POMC neurons does not produce any effect on basal nociception but inhibits stress-induced analgesia (unlike inhibition of arcuate POMC neurons). Activation of NTS POMC neuronal populations in conscious mice did not cause respiratory depression, anxiety, or locomotor deficit (in open field) or affective preference. These findings indicate that NTS POMC neurons play a key role in the generation of endorphinergic endogenous analgesia and can also regulate cardiorespiratory function.

Evaluation of ameliorative effect of two selected plant drugs on experimentally induced arsenic toxicity in sheep.

Chronic arsenic poisoning is one of the serious health hazards in West Bengal, India, and Bangladesh. It occurs due to contaminated subsoil water. The aim of this study is conducted to find out the ameliorative effect of turmeric and P. foetida powder on experimentally induced arsenic toxicity in sheep. Twelve sheep were divided into four groups; groups I, II and III were orally administered with sodium arsenite at 6.6 mg/kg body weight for 133 days; groups I and II animals were treated by turmeric and P. foetida powders respectively at 500 mg/kg dose for the last 49 days; the fourth group was control. Arsenic content was estimated in faeces, urine and wool in every 15 days. Biochemical, haematological, antioxidant parameters and DNA fragmentation were also assessed. Turmeric and P. foetida powder treatment significantly (P < 0.05) increased arsenic elimination through faeces, urine and wool. Haemoglobin content and TEC were decreased in groups I, II and III; however, these were improved significantly (P < 0.05) by turmeric and P. foetida powder treatment. Increased activity of AST, ALT, blood urea nitrogen and plasma creatinine were significantly (P < 0.05) decreased in groups I and II. The reduced SOD and catalase activity were significantly (P < 0.05) restored at the end of the experiment in turmeric and P. foetida-treated groups. The test drugs are found significantly effective not only to eliminate arsenic from the body but also give protection from possible damage caused by arsenic exposure in sheep.

Cannabidiol improves survival and behavioural co-morbidities of Dravet syndrome in mice.

BACKGROUND AND PURPOSE: Dravet syndrome is a severe, genetic form of paediatric epilepsy associated with premature mortality and co-morbidities such as anxiety, depression, autism, motor dysfunction and memory deficits. Cannabidiol is an approved anticonvulsive drug in the United States and Europe for seizures associated with Dravet syndrome in patients 2 years of age and older. We investigated its potential to prevent premature mortality and improve associated co-morbidities. EXPERIMENTAL APPROACH: The efficacy of sub-chronic cannabidiol administration in two mouse models of Dravet syndrome was investigated. The effect of cannabidiol on neonatal welfare and survival was studied using Scn1a-/- mice. We then used a hybrid, heterozygote Scn1a+/- mouse model to study the effect of cannabidiol on survival and behavioural co-morbidities: motor deficits (rotarod and static-beam test), gait abnormality (gait test), social anxiety (social interaction test), anxiety-like (elevated plus maze) and depressive-like behaviours (sucrose preference test) and cognitive impairment (radial arm maze test). KEY RESULTS: In Scn1a-/- mice, cannabidiol increased survival and delayed worsening of neonatal welfare. In Scn1a+/- mice, chronic cannabidiol administration did not show any adverse effect on motor function and gait, reduced premature mortality, improved social behaviour and memory function, and reduced anxiety-like and depressive-like behaviours. CONCLUSION AND IMPLICATIONS: We are the first to demonstrate a potential disease-modifying effect of cannabidiol in animal models of Dravet syndrome. Cannabidiol treatment reduced premature mortality and improved several behavioural co-morbidities in Dravet syndrome mice. These crucial findings may be translated into human therapy to address behavioural co-morbidities associated with Dravet syndrome.

Cannabidiol reduces seizures and associated behavioral comorbidities in a range of animal seizure and epilepsy models.

OBJECTIVE: Epilepsy is a progressive neurological disease characterized by recurrent seizures and behavioral comorbidities. We investigated the antiseizure effect of cannabidiol (CBD) in a battery of acute seizure models. Additionally, we defined the disease-modifying potential of chronic oral administration of CBD on associated comorbidities in the reduced intensity status epilepticus-spontaneous recurrent seizures (RISE-SRS) model of temporal lobe epilepsy (TLE). METHODS: We evaluated the acute antiseizure effect of CBD in the maximal electroshock seizure, 6-Hz psychomotor seizure, and pentylenetetrazol acute seizure tests, as well as the corneal kindling model of chronic seizures in mice following intraperitoneal administration. Median effective or behavioral toxic dose was determined in both mice and rats. Next, we tested an intravenous preparation of CBD (10 mg/kg single dose) in a rat model of pilocarpine-induced status epilepticus. We defined the effect of chronic CBD administration (200 mg/kg orally) on spontaneous seizures, motor control, gait, and memory function in the rat RISE-SRS model of TLE. RESULTS: CBD was effective in a battery of acute seizure models in both mice and rats following intraperitoneal administration. In the pilocarpine-induced status epilepticus rat model, CBD attenuated maximum seizure severity following intravenous administration, further demonstrating CBD's acute antiseizure efficacy in this rat model. We established that oral CBD attenuated the time-dependent increase in seizure burden and improved TLE-associated motor comorbidities of epileptic rats in the RISE-SRS model without affecting gait. Chronic administration of CBD after the onset of SRS ameliorated reference memory and working memory errors of epileptic animals in a spatial learning and memory task. SIGNIFICANCE: The present study illustrates that CBD is a well-tolerated and effective antiseizure agent and illustrates a potential disease-modifying effect of CBD on reducing both seizure burden and associated comorbidities well after the onset of symptomatic seizures in a model of TLE.

Ameliorative Effect of Tephrosia Purpurea in Arsenic-induced Nephrotoxicity in Rats.

OBJECTIVES: The present investigation was conducted to evaluate the nephroprotective activity of Tephrosia purpurea (TPE) against arsenic-induced toxicity. MATERIALS AND METHODS: Twenty four number of wistar rats were equally divided into three groups. Sodium arsenite (10 mg/kg) was orally given to group I for 28 days, additionally group II was orally treated with TPE (500 mg/kg), while the control group was kept untreated with neither arsenic nor TPE. Serum biomarker levels, oxidative stress indices and arsenic concentration in kidney were estimated. Histopathology of kidney was also conducted. RESULTS: Group II animals show significantly reduced blood urea nitrogen and plasma creatinine, and increased serum albumin level compared to group I. The higher lipid peroxidation with exhausted superoxide dismutase activity and reduced glutathione level were noticed in group I compared to group II. There was no significant difference in arsenic accumulation in kidneys between the two arsenic treated groups, but the histopathology of kidney of group II rats revealed reduced necrosis and intact tubular architecture as compared to group I. CONCLUSIONS: Tephrosia Purpurea extract has a significant role in protecting the animals from arsenic-induced nephrotoxicity.

Immunotoxic and genotoxic potential of arsenic and its chemical species in goats.

The study investigated the immunotoxic and genotoxic effect of arsenic and its different species on goats. It was found that arsenic causes haematological crisis. Histopathological changes in spleen and reduced serum immunoglobulin G level without any changes in formazan production in arsenic-treated animals indicated that arsenic is toxic to the humoral immune system. Increased caspase-3 production and higher number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling)-positive bone marrow cells along with oligonucleosomal DNA fragmentation on agarose gel suggested apoptosis induction by arsenic in the bone marrow cells of goat. Total arsenic concentration in the plasma, bone marrow, and spleen of the exposed group was, respectively, 1.22 ± 0.11, 2.20 ± 0.21, and 3.39 ± 0.14 ppm. Speciation study revealed that arsenite and organoarsenic were the major arsenic species in these samples, suggesting their role in immunotoxic and genotoxic potential in goats.

Disposition of ceftriaxone in hepatopathic goats following single-intramuscular dosing.

Hepatopathy sometimes may interfere with metabolism and/or elimination of drugs which undergo major hepatic clearance. Twelve healthy goats were equally divided into two groups (I and II) and hepatopathy was induced by carbontetrachloride in the second group (group II). A single dose of ceftriaxone at 50 mg/kg was administered to each group intramuscularly. Disposition of ceftriaxone in plasma of healthy goats showed a typical absorption-reabsorption phase. However, the reabsorption phase was totally absent in hepatopathic goats and the disposition of ceftriaxone showed only absorption and distribution/elimination phase. The drug persisted in plasma for 6 h in hepatopathic animals, whereas the drug can only be detected up to 2 h in healthy animals indicating longer persistence of ceftriaxone in the former group. Ceftizoxime, the active metabolite of ceftriaxone was available in urine of group I animals, whereas only ceftriaxone was detected in the urine of hepatopathic animals suggesting impairment of metabolism of the parent drug in hepatopathy. Therefore, the reabsorption and metabolism of ceftriaxone in goats should be taken into consideration for drug monitoring.

Effect of environmental exposure of arsenic on cattle and poultry in nadia district, west bengal, India.

A study was undertaken to evaluate an alternative source of arsenicosis in human food chain through livestock. Thirty milch cattle and 20 poultry birds along with their eggs were selected randomly from two endemic villages of Nadia district and one nonendemic villages of Hooghly district in West Bengal, India. Milk, feces, urine, and hair samples of cattle and feed materials, such as water and straw, were collected to analyze arsenic status. Arsenic concentration in egg yolk and albumen from poultry eggs and different poultry organs after culling was estimated. Distribution of arsenic in animal body indicates that major portion of arsenic was eliminated through feces, urine, and milk. Poultry egg yolk, albumen, and poultry products retain arsenic in all organs. Cows and poultry birds reared in endemic zone retain significantly higher concentration of arsenic. Consumption of egg, agricultural produces grown in contaminated soil, and milk might have produced arsenicosis and may be considered as alternative source of arsenic contamination.

Quantitative imaging of arsenic and its species in goat following long term oral exposure.

Severity of arsenic toxicity was reported to vary depending on its species. The present study reflects the status of different species of arsenic in goat following long-term exposure of arsenic leading to hepatic damage. The experiment was conducted with six black Bengal goats, which were administered with sodium arsenite orally at a dose rate of 2 mgkg(-1) daily for 84 days. Faeces, urine, hair and blood samples were collected from those animals at 14 days interval. Excretion of total arsenic was reduced from 56 days onwards through both faeces and urine indicating higher accumulation of arsenic in body. The speciation study revealed that urinary arsenic was mainly of organic type, whereas hair accumulated almost equal proportion of arsenite, arsenate and organo arsenicals. Goats excreted high proportion of organo arsenicals through faeces possibly due to hepatobiliary secretion of organo arsenic into the gut. Significantly elevated serum alanine aminotransferase and aspartate aminotransferase activities (p<0.05) along with histopathological changes in liver indicated hepatotoxicity. The arsenite fraction increased and organic proportion decreased in urine as the time progressed, which indicates that arsenite gets methylated in liver of goat. The study thus alluded that the toxicity of arsenic would aggravate if the animals were exposed for long time as the hepatotoxicity progressed resulting in decreased methylation and formation of organo arsenicals and decreased excretions through urine.

Pharmacokinetic interaction of intramammary ceftriaxone and oral polyherbal drug (Fibrosin(®)) in goats.

BACKGROUND: The aim of the present study was to determine pharmacokinetic interaction of ceftriaxone and polyherbal drug (Fibrosin(®)) in lactating goats following single dose intramammary administration of ceftriaxone with 1 h pre-single dose oral administration of Fibrosin(®). METHODS: Pharmacokinetic interaction of ceftriaxone and Fibrosin(®) was evaluated in lactating goats following single dose intramammary administration of ceftriaxone at 50 mg/kg with 1 h pre-single dose oral administration of Fibrosin(®) (1.9 g). Estimation of ceftriaxone and its metabolite, ceftizoxime, was determined by high performance liquid chromatography. RESULTS: Fibrosin(®) treated goats showed a typical absorption-reabsorption phase of ceftriaxone in plasma following intramammary administration. Neither ceftriaxone nor ceftizoxime was detected in the plasma and urine of goats without Fibrosin(®) treatment, however, ceftriaxone persisted for 36 h and ceftizoxime was present from 48 h to 72 h in the plasma of Fibrosin(®) treated goats. Ceftizoxime was also available from 72 h to 360 h post-dosing in milk in the presence of Fibrosin(®) following intramammary administration of ceftriaxone suggesting the polyherbal drug played a major role in the penetration of ceftriaxone from milk to systemic circulation. Furthermore, the polyherbal drug increased the bioavailability of ceftizoxime in milk following the metabolism of ceftriaxone. CONCLUSIONS: Polyherbal drug (Fibrosin(®)) plays a major role in the penetration of ceftriaxone from milk to systemic circulation and may be responsible for increased bioavailability of its metabolite in the mammary gland resulting in higher concentration and longer persistence of the drug in milk.