Chronic Morphine Modulates the Contents of the Endocannabinoid, 2-Arachidonoyl Glycerol, in Rat Brain

Opioids and cannabinoids are among the most widely consumed drugs of abuse in humans and the phenomena of cross-tolerance or mutual potentiation have been demonstrated between the two drugs. Several authors have suggested that both drugs share common links in their molecular mechanisms of action, although this has been a matter of controversy. Furthermore, no data exist on the possible adaptive changes in the contents of arachidonoylethanolamide (anandamide, AEA) and 2-arachidonoylglycerol (2-AG), the two major endogenous ligands for cannabinoid receptors, in morphine-tolerant rats. In the present work, we investigated the alterations in cannabinoid receptor functionality and endocannabinoid levels in rats chronically treated with morphine (5 mg/kg, s.c., twice a day for 5 days). Autoradiographic-binding studies using [(3)H]CP-55 940 revealed a slight but significant reduction in cannabinoid receptor level in the cerebellum and hippocampus of morphine-tolerant rats, while CP-55 940-stimulated [(35)S]GTPgammaS binding showed a strong decrease (40%) in receptor/G protein coupling in the limbic area of these animals. Moreover, in the same brain regions we measured, by isotope-dilution gas chromatography/mass spectrometry, the contents of AEA and 2-AG. Chronic morphine exposure produced a strong reduction in 2-AG contents without changes in AEA levels in several brain regions (ie striatum, cortex, hippocampus, limbic area, and hypothalamus). These findings clearly demonstrate that prolonged activation of opioid receptors could alter the cannabinoid system, in terms of both receptor functionality and endocannabinoid levels, and suggest the involvement of this system, alone or in combination with other mediators, in the phenomenon of morphine tolerance

Dissociation of the pharmacological effects of THC by mTOR blockade

The potential therapeutic benefits of cannabinoid compounds have raised interest in understanding the molecular mechanisms that underlie cannabinoid-mediated effects. We previously showed that the acute amnesic-like effects of delta9-tetrahydrocannabinol (THC) were prevented by the subchronic inhibition of the mammalian target of rapamycin (mTOR) pathway. In the present study, we assess the relevance of the mTOR pathway in other acute and chronic pharmacological effects of THC. The rapamycin derivative temsirolimus, an inhibitor of the mTOR pathway approved by the Food and Drug Administration, prevents both the anxiogenic- and the amnesic-like effects produced by acute THC. In contrast, THC-induced anxiolysis, hypothermia, hypolocomotion, and antinociception are not sensitive to the mTOR inhibition. In addition, a clear tolerance to THC-induced anxiolysis, hypothermia, hypolocomotion, and antinociception was observed after chronic treatment, but not to its anxiogenic- and amnesic-like effects. Temsirolimus pre-treatment prevented the amnesic-like effects of chronic THC without affecting the downregulation of CB1 receptors (CB1R) induced by this chronic treatment. Instead, temsirolimus blockade after chronic THC cessation did not prevent the residual cognitive deficit produced by chronic THC. Using conditional knockout mice lacking CB1R in GABAergic or glutamatergic neurons, we found that GABAergic CB1Rs are mainly downregulated under chronic THC treatment conditions, and CB1-GABA-KO mice did not develop cognitive deficits after chronic THC exposure. Therefore, mTOR inhibition by temsirolimus allows the segregation of the potentially beneficial effects of cannabinoid agonists, such as the anxiolytic and antinociceptive effects, from the negative effects, such as anxiogenic- and amnesic-like responses. Altogether, these results provide new insights for targeting the endocannabinoid system in order to prevent possible side effects.EP and AB-G were recipients of a predoctoral fellowship, Ministerio de Educación y Cultura. This work was supported by grants from the Ministerio de Ciencia e Innovación (#SAF2009-07309 to AO and # SAF2011-29864 to RM), Instituto de Salud Carlos III (RD06/0001/0001 to RM), PLAN E/n(Plan Español para el Estímulo de la Economía y el Empleo), the European Commission/n(PHECOMP #LSHM-CT-2007-037669 to RM), Generalitat de Catalunya (SGR-2009-00731/nto RM), INSERM to GM, European Research Council (ENDOFOOD, ERC-2010-StG-/n260515, to GM), Fondation pour la Recherche Medicale to GM, and ICREA (Institució Catalana de Recerca i Estudis Avançats) Academia to R

Subaltern Modernity: Kerala, the Eastern Theatre of Resistance in the Global South

In engaging with the debate on modernity, this article constructs the notion of a ‘subaltern modernity’ as a process of epistemological – spatial/temporal/agential – coalescence constituting a transverse solidarity politics. This is empirically informed by the narratives of the livelihood-environmental resistance launched by subalterns in the Indian state of Kerala, known for its twin legacies – of communist government and social development – which have proved to be a direct challenge to the state/corporate-led developmentalism in the region. The article thus attempts to contribute to the debate on modernity more from the perspective of resisting subjects and agents, with their particular subjective experience and understandings of science and reasoning. However, their resistance generates transformative events of universal relevance and thereby global issues of epistemology. As such, the article develops a theory of knowledge that takes subaltern resistance itself as modernity

Preclinical and clinical trials of Indian medicinal plants in disease control

Since the ancient period, the medicinal plants have been used in pharmaceutical and cosmetic industries. Recently, it has gained extreme research importance for their nutraceuticals values. It has been confirmed by WHO that herbal medicines serve the health needs of about 80% of World’s population; especially for millions of people in the vast rural areas of developing countries. This book chapter summarizes the importance of several medicinal plants which are traditionally used in treatment and management of different ailments in India. In addition, some pharmacological models describe the possible mechanism of action of bioactive phytochemicals, which can be successfully used as drug candidates in near future. However, there is urgent need for basic scientific investigations on medicinal plants and this has been highlighted in current research trends in clinical trials