Review of cannabinoids and their antiemetic effectiveness.

Abstract

“Marijuana has been used for over 2 centuries. Its major psychoactive constituent, delta-9-tetrahydrocannabinol (THC) was isolated in 1964 and first used to control nausea and vomiting during chemotherapy in the 1970s. THC has cardiovascular, pulmonary and endocrinological effects as well as actions on the central nervous system. Alterations in mood, memory, motor coordination, cognitive ability, sensorium, spatial- and self-perception are commonly experienced. The precise antiemetic mechanism is unknown. THC and nabilone act at a number of sites within the central nervous system. Cannabinoids have also been shown to inhibit prostaglandin synthesis in vitro. In controlled clinical trials, THC is superior to placebo and prochlorperazine in antiemetic effectiveness. Effectiveness of THC correlates to a ‘high’ experienced by the patient. A variety of chemotherapy regimens respond to THC including high-dose methotrexate and the doxorubicin, cyclophosphamide, fluorouracil combination. Cisplatin is more resistant. Side effects are generally well tolerated but may limit THC use in the elderly or when high doses are administered. Nabilone, a synthetic cannabinoid, is also an effective antiemetic which is more active than prochlorperazine in preventing chemotherapy-induced emesis, including cisplatin-containing regimens. Side effects are similar to THC and may be dose-limiting. Levonantradol, another synthetic cannabinoid, is an effective antiemetic. It may provide more flexibility in the outpatient setting since it can be administered orally or intramuscularly. Most side effects are mild except for dysphoria which may be dose-limiting.”

http://www.ncbi.nlm.nih.gov/pubmed/6301800

An electrophysiological analysis of the anticonvulsant action of cannabidiol on limbic seizures in conscious rats.

Abstract

“The effects of cannabidiol (CBD) on electrically evoked kindled seizures were studied in conscious, unrestrained rats with chronically implanted cortical and limbic electrodes, and the results were compared with those of delta 9-tetrahydrocannabinol (delta 9-THC), phenytoin (PHT), and ethosuximide (ESM). All drugs were anticonvulsant, but there were marked differences in their effects on afterdischarge (AD) threshold, duration, and amplitude. CBD, like PHT and delta 9-THC, elevated the AD threshold; in contrast, ESM decreased the threshold but suppressed AD spread. CBD, however, also resembled ESM inasmuch as both drugs decreased AD duration and amplitude. Electrophysiologically, the antiseizure effects of CBD were a combination of those of PHT and ESM. The combination of effects may account for the observation that CBD was the most efficacious of the drugs tested against limbic ADs and convulsions. Other properties of CBD were also noted: For example, compared with delta 9-THC, it is a much more selective anticonvulsant vis-à-vis motor toxicity. CBD also lacks the CNS excitatory effects produced by delta 9-THC, PHT, and ESM. These characteristics, combined with its apparently unique set of electrophysiological properties, support the suggestion that CBD has therapeutic potential as an antiepileptic.”

http://www.ncbi.nlm.nih.gov/pubmed/477630

Epileptiform seizures in domestic fowl. V. The anticonvulsant activity of delta9-tetrahydrocannabinol.

Abstract

“The anticonvulsant activity of delta9-tetrahydrocannabinol (delta9-THC) has been determined against seizures induced in epileptic chickens by intermittent photic stimulation (IPS) and in epileptic and nonepileptic chickens by Metrazol. Intravenous administration of the drug reduced both the severity and incidence of seizures evoked by IPS in epileptic chickens. This anticonvulsant action was accompanied by a reduction in frequency of inter-ictal slow-wave high-voltage electroencephalographic activity and by the absence of spiking during IPS. delta9-THC did not affect the incidence of Metrazol-induced seizures in epileptic or nonepileptic chickens.”

http://www.ncbi.nlm.nih.gov/pubmed/1222370

Anticonvulsant activity of delta9-tetrahydrocannabinol compared with three other drugs.

Abstract

“Delta9-tetrahydrocannabinol (THC) was compared with diphenylhydantoin (DPH), phenobarbital (PB) and chlordiazepoxide (CDP) using several standard laboratory procedures to determine anticonvulsant activity in mice, i.e., the maximal electroshock test (MES), and seizures induced by pentylenetetrazol, strychnine and nicotine. In the MES test, THC was the least potent and DPH the most potent blocker of hind limb tonic extensor convulsions whereas THC was the most potent and DPH the least potent in increasing the latency to this response and in preventing mortality. Seizures and mortality induced by pentylenetetrazol or by strychnine were enhanced by THC and DPH and were blocked by PB and CDP. In the test with nicotine, none of the four anticonvulsant agents prevented seizures; DPH was the only one which failed to increase latency; THC and DPH were less potent than PB and CDP in preventing mortality. THC most closely resembled DPH in the tests with chemical convulsant agents, but a sedative action of THC, resembling that of PB and CDP, was indicated by low ED5 0 for increased latency and for prevention of mortality in the MES test.”

http://www.ncbi.nlm.nih.gov/pubmed/1253828

Anticonvulsant action of cannabis in the rat: role of brain monoamines.

Abstract

“The role of brain monoamines in the anticonvulsant action of Cannabis indica resin (CI), against maximal electroshock-induced seizures in albino rats, was investigated by using pharmacologic agents that influence brain monoamine activity. Delta-9-tetrahydrocannabinol content of cannabis resin was estimated to be 17%. The anticonvulsant action of CI (200 mg/kg, i.p.) was significantly inhibited after pretreatment with drugs that reduce brain serotonin activity but not by drugs that reduce brain catecholamine activity. Similarly, the anticonvulsant action of a subanticonvulsant dose (50 mg/kg, i.p.) of CI was potentiated by serotonin precursors but not by catecholamine precursors. Potentiation of the anticonvulsant action of CI by nialamide or by imipramine was inhibited after pretreatment with 5,6-dihydroxytryptamine. The results suggest that the anticonvulsant action of CI in the rat is serotonin- and not catecholamine-mediated.”

http://www.ncbi.nlm.nih.gov/pubmed/104333

The cannabinoid acids: nonpsychoactive derivatives with therapeutic potential.

Abstract

   “The discovery of carboxylic acid metabolites of the cannabinoids (CBs) dates back more than three decades. Their lack of psychotropic activity was noted early on, and this resulted in a total absence of further research on their possible role in the actions of the CBs. More recent studies have revealed that the acids possess both analgesic and anti-inflammatory properties and may contribute to the actions of the parent drug. A synthetic analog showed similar actions at considerably lower doses. In this review, a brief survey of the extensive literature on metabolism of delta 9-tetrahydrocannabinol to the acids is presented, while more emphasis is given to the recent findings on the biological actions of this class of CBs. A possible mechanism involving effects on eicosanoids for some of these actions is also suggested. Finally, an analogy with a putative metabolite of anandamide, an endogenous CB, is discussed.”

http://www.ncbi.nlm.nih.gov/pubmed/10341359

Ajulemic acid: A novel cannabinoid produces analgesia without a “high”.

Abstract

   “A long-standing goal in cannabinoid research has been the discovery of potent synthetic analogs of the natural substances that might be developed as clinically useful drugs. This requires, among other things, that they be free of the psychotropic effects that characterize the recreational use of Cannabis. An important driving force for this goal is the long history of the use of Cannabis as a medicinal agent especially in the treatment of pain and inflammation. While few compounds appear to have these properties, ajulemic acid (AJA), also known as CT-3 and IP-751, is a potential candidate that could achieve this goal. Its chemical structure was derived from that of the major metabolite of Delta9-THC, the principal psychotropic constituent of Cannabis. In preclinical studies it displayed many of the properties of non-steroidal anti-inflammatory drugs (NSAIDs); however, it seems to be free of undesirable side effects. The initial short-term trials in healthy human subjects, as well as in patients with chronic neuropathic pain, demonstrated a complete absence of psychotropic actions. Moreover, it proved to be more effective than placebo in reducing this type of pain as measured by the visual analog scale. Unlike the narcotic analgesics, signs of dependency were not observed after withdrawal of the drug at the end of the one-week treatment period. Data on its mechanism of action are not yet complete; however, the activation of PPAR-gamma, and regulation of eicosanoid and cytokine production, appear to be important for its potential therapeutic effects.”

http://www.ncbi.nlm.nih.gov/pubmed/15240185

Antihyperalgesic properties of the cannabinoid CT-3 in chronic neuropathic and inflammatory pain states in the rat.

Abstract

   “CT-3 (ajulemic acid) is a synthetic analogue of a metabolite of Delta9-tetrahydrocannabinol that has reported analgesic efficacy in neuropathic pain states in man. Here we show that CT-3 binds to human cannabinoid receptors in vitro, with high affinity at hCB1 (Ki 6 nM) and hCB2 (Ki 56 nM) receptors. In a functional GTP-gamma-S assay CT-3 was an agonist at both hCB1 and hCB2 receptors (EC50 11 and 13.4 nM, respectively). In behavioural models of chronic neuropathic and inflammatory pain in the rat, oral administration of CT-3 (0.1-1 mg/kg) produced up to 60% reversal of mechanical hyperalgesia. In both models the antihyperalgesic activity was prevented by the CB1-antagonist SR141716A but not the CB2-antagonist SR144528. In the tetrad of tests for CNS activity, CT-3 (1-10 mg/kg, po) produced dose-related catalepsy, deficits in locomotor performance, hypothermia, and acute analgesia. Comparison of 50% maximal effects in the tetrad and chronic pain assays produced an approximate therapeutic index of 5-10. Pharmacokinetic analysis showed that CT-3 exhibits significant but limited brain penetration, with a brain/plasma ratio of 0.4 measured following oral administration, compared to ratios of 1.0-1.9 measured following subcutaneous administration of WIN55,212-2 or Delta9-THC. These data show that CT-3 is a cannabinoid receptor agonist and is efficacious in animal models of chronic pain by activation of the CB1 receptor. Whilst it shows significant cannabinoid-like CNS activity, it exhibits a superior therapeutic index compared to other cannabinoid compounds, which may reflect a relatively reduced CNS penetration.”

http://www.ncbi.nlm.nih.gov/pubmed/15936883

Potential antipsychotic properties of central cannabinoid (CB1) receptor antagonists.

Abstract

“Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the principal psychoactive constituent of the Cannabis sativa plant, and other agonists at the central cannabinoid (CB(1)) receptor may induce characteristic psychomotor effects, psychotic reactions and cognitive impairment resembling schizophrenia. These effects of Delta(9)-THC can be reduced in animal and human models of psychopathology by two exogenous cannabinoids, cannabidiol (CBD) and SR141716. CBD is the second most abundant constituent of Cannabis sativa that has weak partial antagonistic properties at the CB(1) receptor. CBD inhibits the reuptake and hydrolysis of anandamide, the most important endogenous CB(1) receptor agonist, and exhibits neuroprotective antioxidant activity. SR141716 is a potent and selective CB(1) receptor antagonist. Since both CBD and SR141716 can reverse many of the biochemical, physiological and behavioural effects of CB(1) receptor agonists, it has been proposed that both CBD and SR141716 have antipsychotic properties. Various experimental studies in animals, healthy human volunteers, and schizophrenic patients support this notion. Moreover, recent studies suggest that cannabinoids such as CBD and SR141716 have a pharmacological profile similar to that of atypical antipsychotic drugs. In this review, both preclinical and clinical studies investigating the potential antipsychotic effects of both CBD and SR141716 are presented together with the possible underlying mechanisms of action.”

http://www.ncbi.nlm.nih.gov/pubmed/20218784

Marijuana Compound Effective In Treating Tourette’s Syndrome, Study Says

“Thursday, 15 May 2003

Hanover, Germany: A primary compound in marijuana, delta-9-tetrahydrocannabinol (THC), is effective in reducing “tics” in patients suffering from Tourette’s Syndrome (TS), according to clinical trail data published in a recent edition of the Journal of Clinical Psychiatry. Tourette’s Syndrome is a complex neuropsychiatric disorder characterized by motor tics (sudden spasms especially in the facial muscles, neck and shoulders) and one or more vocal tics.

Twenty-four patients participated in the double-blind placebo-controlled trial over a period of six weeks. Treatment with up to 10 mg of THC resulted in significant improvement of tic severity, authors wrote. No serious adverse effects to the treatment were reported.

In a separate article published in Neuropsychopharmacology, authors elaborated, “No detrimental effect was seen on learning curve, interference, recall and recognition of word lists, immediate visual memory span, and divided attention” from THC during or after the treatment.

The 24-patient study confirmed previous smaller patient trials that also found THC to be effective in the treatment of tics and behavioral problems in patients with Tourette’s Syndrome.”

http://norml.org/news/2003/05/15/marijuana-compound-effective-in-treating-tourette-s-syndrome-study-says