Tag Archives: CB1

Type 1 cannabinoid receptor modulates water deprivation-induced homeostatic responses.

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“The present study investigated the type 1 cannabinoid receptor (CB1R) as a potential candidate to mediate the homeostatic responses triggered by 24 hours of water deprivation (WD), which constitutes primarily a hydroelectrolytic challenge and also significantly impacts energy homeostasis.

The present results demonstrated for the first time that CB1R mRNA expression is increased in the hypothalamus of WD rats. Furthermore, the administration of ACEA, a CB1R selective agonist, potentiated WD-induced dipsogenic effect, whereas AM251, a CB1R antagonist, attenuated not only water but also salt intake in response to WD. In parallel with the modulation of thirst and salt appetite, we confirmed that CB1Rs are essential for the development of appropriated neuroendocrine responses…

In conclusion, the present study demonstrated that CB1Rs participate in the homeostatic responses regulating fluid balance and energy homeostasis during WD.”

http://www.ncbi.nlm.nih.gov/pubmed/26468265

CB1 receptor antagonism blocks stress-potentiated reinstatement of cocaine seeking in rats.

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“Under some conditions, stress, rather than directly triggering cocaine seeking, potentiates reinstatement to other stimuli, including a subthreshold cocaine dose.

Endocannabinoid signaling is increased by stress and regulates synaptic transmission in brain regions implicated in motivated behavior.

The objective of this study was to test the hypothesis that cannabinoid type 1 receptor (CB1R) signaling is required for stress-potentiated reinstatement of cocaine seeking in rats…

These findings demonstrate that footshock stress increases prefrontal cortical endocannabinoids and stress-potentiated reinstatement is CB1R-dependent, suggesting that CB1R is a potential therapeutic target for relapse prevention, particularly in individuals whose cocaine use is stress-related.”

http://www.ncbi.nlm.nih.gov/pubmed/26455361

Cannabinoids produce neuroprotection by reducing intracellular calcium release from ryanodine-sensitive stores.

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“Exogenously administered cannabinoids are neuroprotective in several different cellular and animal models.

In the current study, two cannabinoid CB1 receptor ligands (WIN 55,212-2, CP 55,940) markedly reduced hippocampal cell death, in a time-dependent manner, in cultured neurons subjected to high levels of NMDA…

The results suggest that cannabinoids prevent cell death by initiating a time and dose dependent inhibition of adenylyl cyclase, that outlasts direct action at the CB1 receptor and is capable of reducing [Ca2+](i) via a cAMP/PKA-dependent process during the neurotoxic event.”

http://www.ncbi.nlm.nih.gov/pubmed/15910885

Protection from Radiation-Induced Pulmonary Fibrosis by Peripheral Targeting of Cannabinoid Receptor-1.

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“Radiation-induced pulmonary fibrosis (RIF) is a severe complication of thoracic radiotherapy that limits its dose, intensity, and duration. The contribution of the endocannabinoid signaling system in pulmonary fibrogenesis is not known. Using a well-established mouse model of RIF, we assessed the involvement of cannabinoid receptor-1 (CB1) in the onset and progression of pulmonary fibrosis.

Our results show that CB1 signaling plays a key pathological role in the development of radiation-induced pulmonary inflammation and fibrosis, and peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating complication of radiotherapy/irradiation.”

http://www.ncbi.nlm.nih.gov/pubmed/26426981

“We report for the first time the involvement of cannabinoid receptor 1 (CB1)-mediated signaling in the onset and progression of radiation-induced pulmonary fibrosis (RIF). We were able to delay the onset of RIF by genetic targeting of CB1 receptors as well as by its pharmacological inhibition. Thus, pharmacological targeting of CB1 receptors with peripherally restricted CB1 antagonists void of central nervous system complications may represent a novel strategy to prevent the development of RIF.

In summary, we provide the first evidence on the key pathological role of CB1 signaling in radiation-induced pulmonary fibrogenesis and show that peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating and untreatable complication of radiotherapy/irradiation. Our results also suggest that targeting CB1 may provide benefits in other lung diseases associated with inflammation and fibrosis.”

http://www.atsjournals.org/doi/10.1165/rcmb.2014-0331OC

The Endocannabinoid System: Pivotal Orchestrator of Obesity and Metabolic Disease.

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“The endocannabinoid system (ECS) functions to adjust behavior and metabolism according to environmental changes in food availability.

Its actions range from the regulation of sensory responses to the development of preference for the consumption of calorically-rich food and control of its metabolic handling.

ECS activity is beneficial when access to food is scarce or unpredictable.

However, when food is plentiful, the ECS favors obesity and metabolic disease.

We review recent advances in understanding the roles of the ECS in energy balance, and discuss newly identified mechanisms of action that, after the withdrawal of first generation cannabinoid type 1 (CB1) receptor antagonists for the treatment of obesity, have made the ECS once again an attractive target for therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/26412154

https://www.cell.com/trends/endocrinology-metabolism/fulltext/S1043-2760(15)00140-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS104327601500140X%3Fshowall%3Dtrue

Endocannabinoids and Metabolic Disorders.

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“The endocannabinoid system (ECS) is known to exert regulatory control on essentially every aspect related to the search for, and the intake, metabolism and storage of calories, and consequently it represents a potential pharmacotherapeutic target for obesity, diabetes and eating disorders.

While the clinical use of the first generation of cannabinoid type 1 (CB1) receptor blockers has been halted due to the psychiatric side effects that their use occasioned, recent research in animals and humans has provided new knowledge on the mechanisms of actions of the ECS in the regulation of eating behavior, energy balance, and metabolism.

In this review, we discuss these recent advances and how they may allow targeting the ECS in a more specific and selective manner for the future development of therapies against obesity, metabolic syndrome, and eating disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26408168

Endocannabinoids and the Endocrine System in Health and Disease.

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“Some of the earliest reports of the effects of cannabis consumption on humans were related to endocrine system changes. In this review, the effects of cannabinoids and the role of the CB1 cannabinoid receptor in the regulation of the following endocrine systems are discussed: the hypothalamic-pituitary-gonadal axis, prolactin and oxytocin, thyroid hormone and growth hormone, and the hypothalamic-pituitary-adrenal axis. Preclinical and human study results are presented.”

http://www.ncbi.nlm.nih.gov/pubmed/26408166

Genetic Manipulation of the Endocannabinoid System.

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“The physiological and pathophysiological functions of the endocannabinoid system have been studied extensively using transgenic and targeted knockout mouse models.

The first gene deletions of the cannabinoid CB1 receptor were described in the late 1990s, soon followed by CB2 and FAAH mutations in early 2000.

These mouse models helped to elucidate the fundamental role of endocannabinoids as retrograde transmitters in the CNS and in the discovery of many unexpected endocannabinoid functions, for example, in the skin, bone and liver.

We now have knockout mouse models for almost every receptor and enzyme of the endocannabinoid system.

Conditional mutant mice were mostly developed for the CB1 receptor, which is widely expressed on many different neurons, astrocytes and microglia, as well as on many cells outside the CNS.

These mouse strains include “floxed” CB1 alleles and mice with a conditional re-expression of CB1. The availability of these mice made it possible to decipher the function of CB1 in specific neuronal circuits and cell populations or to discriminate between central and peripheral effects.

Many of the genetic mouse models were also used in combination with viral expression systems.

The purpose of this review is to provide a comprehensive overview of the existing genetic models and to summarize some of the most important discoveries that were made with these animals.”

http://www.ncbi.nlm.nih.gov/pubmed/26408160

Cannabinoid receptor activation in the basolateral amygdala blocks the effects of stress on the conditioning and extinction of inhibitory avoidance.

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“The endocannabinoid system has recently emerged as important in the regulation of extinction learning and in the regulation of the hypothalamic-pituitary-adrenal axis.

Here, we aimed to examine the involvement of the cannabinoid CB(1) receptor in the basolateral amygdala (BLA) in inhibitory avoidance (IA) conditioning and extinction and to test whether cannabinoid activation would reverse the effects of stress on these memory processes.

Together, our findings may support a wide therapeutic application for cannabinoids in the treatment of conditions associated with the inappropriate retention of aversive memories and stress-related disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/19741114

Cannabinoid type-1 receptor signaling in central serotonergic neurons regulates anxiety-like behavior and sociability.

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“The endocannabinoid (eCB) system possesses neuromodulatory functions by influencing the release of various neurotransmitters, including γ-aminobutyric acid (GABA) and glutamate. A functional interaction between eCBs and the serotonergic system has already been suggested.

Previously, we showed that cannabinoid type-1 (CB1) receptor mRNA and protein are localized in serotonergic neurons of the raphe nuclei, implying that the eCB system can modulate serotonergic functions.

In order to substantiate the physiological role of the CB1 receptor in serotonergic neurons of the raphe nuclei, we generated serotonergic 5-hydroxytryptamine (5-HT) neuron-specific CB 1 receptor-deficient mice, using the Cre/loxP system with a tamoxifen-inducible Cre recombinase under the control of the regulatory sequences of the tryptophan hydroxylase 2 gene (TPH2-CreER (T2)), thus, restricting the recombination to 5-HT neurons of the central nervous system (CNS).

Applying several different behavioral paradigms, we revealed that mice lacking the CB1 receptor in serotonergic neurons are more anxious and less sociable than control littermates. Thus, we were able to show that functional CB1 receptor signaling in central serotonergic neurons modulates distinct behaviors in mice.”

http://www.ncbi.nlm.nih.gov/pubmed/26388750