Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344307 (analgesia)
 28,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two subtypes of cannabinoid receptors, CB1 and CB2, have been described to date, although future investigations may elucidate other receptors. The actions of cannabimimetic agents via CB1 receptors in brain are mediated by GI/O to inhibit adenylate cyclase and Ca2+ channels. Little is known about signal transduction mechanisms utilized by CB2 receptors. Three classes of agonist ligands regulate cannabinoid receptors: cannabinoid, aminoalkyl-indole, and eicosanoid derivatives. Cannabinoid receptors produce analgesia and modify cognition, memory, locomotor activity, and endocrine functions in mammals.
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PMID:Pharmacology of cannabinoid receptors. 759 9

Studies using agonists from at least three major cannabinoid ligand groups suggest the mediation of several distinct effects (e.g. psychotropic, analgesia, and antiemetic) by the recently cloned CB1 cannabinoid receptor. However, other studies suggest the presence of multiple cannabinoid receptors and at least one other receptor (CB2) has been cloned. The present investigation was undertaken to determine whether one of the potential therapeutic actions of cannabinoids (i.e. antinociception) is mediated by the CB1 receptor using the antisense oligodeoxynucleotide 'knock-down' approach. Synthetic oligodeoxynucleotides complementary to the 5' end of the coding region of the mouse CB1 receptor mRNA were administered to mice by the intracerebro-ventricular (i.c.v.) route twice daily for 3 days. Mismatch oligodeoxynucleotides of similar sequence, but containing six mismatched positions out of the 18 nucleotides within the oligodeoxynucleotide were administered to other mice. Treatment with antisense oligodeoxynucleotides, but not mismatched oligodeoxynucleotides, greatly inhibited the antinociceptive response of the cannabinoid agonist CP-55,940. Untreated mice and those treated with mismatched oligodeoxynucleotides showed similar, full response antinociception after CP-55,940 administration. The data provides strong evidence that the CB1 receptor-ligand interaction is essential for the antinociceptive effect.
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PMID:Antisense oligodeoxynucleotide treatment to the brain cannabinoid receptor inhibits antinociception. 873 Aug 37

Changes in mitogen-induced splenocyte proliferation and NK activity were evaluated after acute (1 h) and chronic (6 d) in vivo treatment of rats with the synthetic cannabinoid compound CP-55,940. At a dose of 0.4 mg/kg i.p. it significantly inhibited the splenocyte proliferative response to PHA and NK activity but half this dose (0.2 mg/kg) had no effect on immune responses. Pretreatment of rats with the cannabinoid receptor CB1 antagonist SR141716A did not antagonize the CP-55,940-induced immunosuppression, excluding the activation of this receptor subtype in the mediation of this effect. When immune function studies were done on rats tolerant to CP-55,940-induced analgesia, full tolerance also developed for the inhibition of splenocyte proliferation and NK activity. The data provided indicate that CB1 cannabinoid receptors are not involved in mediating the acute and chronic effects of cannabinoids on the immune system and suggest a possible implication of CB2 receptor although other modalities of CP-55,940 action can not be ruled out.
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PMID:Regulation of immune functions in rat splenocytes after acute and chronic in vivo treatment with CP-55,940, a synthetic cannabinoid compound. 941 70

2-Arachidonoyl-glycerol (2-Ara-GI) has been isolated from various tissues and identified as an endogenous ligand for both cannabinoid receptors, CB1 and CB2. Here we report that in spleen, as in brain and gut, 2-Ara-GI is accompanied by several 2-acyl-glycerol esters, two major ones being 2-linoleoyl-glycerol (2-Lino-Gl) and 2-palmitoyl-glycerol (2-Palm-Gl). These two esters do not bind to the cannabinoid receptors, nor do they inhibit adenylyl cyclase via either CB1 or CB2; however, they significantly potentiate the apparent binding of 2-Ara-Gl and its apparent capacity to inhibit adenylyl cyclase. Together these esters also significantly potentiate 2-Ara-Gl inhibition of motor behavior, immobility on a ring, analgesia on a hot plate and hypothermia caused by 2-Ara-Gl in mice. 2-Lino-Gl, but not 2-Palm-GI, significantly inhibits the inactivation of 2-Ara-Gl by neuronal and basophilic cells. These data indicate that the biological activity of 2-Ara-Gl can be increased by related, endogenous 2-acyl-glycerols, which alone show no significant activity in any of the tests employed. This effect ('entourage effect') may represent a novel route for molecular regulation of endogenous cannabinoid activity.
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PMID:An entourage effect: inactive endogenous fatty acid glycerol esters enhance 2-arachidonoyl-glycerol cannabinoid activity. 972 Oct 36

Two subtypes of cannabinoid receptors have been identified to date, the CB1 receptor, essentially located in the CNS, but also in peripheral tissues, and the CB2 receptor, found only at the periphery. The identification of delta9-tetrahydrocannabinol (delta9-THC) as the major active component of marijuana (Cannabis sativa), the recent emergence of potent synthetic ligands and the identification of anandamide and sn-2 arachidonylglycerol as putative endogenous ligands for cannabinoid receptors in the brain, have contributed to advancing cannabinoid pharmacology and approaching the neurobiological mechanisms involved in physiological and behavioral effects of cannabinoids. Most of the agonists exhibit nonselective affinity for CB1/CB2 receptors, and delta9-THC and anandamide probably act as partial agonists. Some recently synthesized molecules are highly selective for CB2 receptors, whereas selective agonists for the CB1 receptors are not yet available. A small number of antagonists exist that display a high selectivity for either CB1 or CB2 receptors. Cannabinomimetics produce complex pharmacological and behavioral effects that probably involve numerous neuronal substrates. Interactions with dopamine, acetylcholine, opiate, and GABAergic systems have been demonstrated in several brain structures. In animals, cannabinoid agonists such as delta9-THC, WIN 55,212-2, and CP 55,940 produce a characteristic combination of four symptoms, hypothermia, analgesia, hypoactivity, and catalepsy. They are reversed by the selective CB1 receptor antagonist, SR 141716, providing good evidence for the involvement of CB1-related mechanisms. Anandamide exhibits several differences, compared with other agonists. In particular, hypothermia, analgesia, and catalepsy induced by this endogenous ligand are not reversed by SR 141716. Cannabinoid-related processes seem also involved in cognition, memory, anxiety, control of appetite, emesis, inflammatory, and immune responses. Agonists may induce biphasic effects, for example, hyperactivity at low doses and severe motor deficits at larger doses. Intriguingly, although cannabis is widely used as recreational drug in humans, only a few studies revealed an appetitive potential of cannabimimetics in animals, and evidence for aversive effects of delta9-THC, WIN 55,212-2, and CP 55,940 is more readily obtained in a variety of tests. The selective blockade of CB1 receptors by SR 141716 impaired the perception of the appetitive value of positive reinforcers (food, cocaine, morphine) and reduced the motivation for sucrose, beer and alcohol consumption, indicating that positive incentive and/or motivational processes could be under a permissive control of CB1-related mechanisms. There is little evidence that cannabinoid systems are activated under basal conditions. However, by using SR 141716 as a tool, a tonic involvement of a CB1-mediated cannabinoid link has been demonstrated, notably in animals suffering from chronic pain, faced with anxiogenic stimuli or highly motivational reinforcers. Some effects of SR 141716 also suggest that CB1-related mechanisms exert a tonic control on cognitive processes. Extensive basic research is still needed to elucidate the roles of cannabinoid systems, both in the brain and at the periphery, in normal physiology and in diseases. Additional compounds, such as selective CB1 receptor agonists, ligands that do not cross the blood brain barrier, drugs interfering with synthesis, degradation or uptake of endogenous ligand(s) of CB receptors, are especially needed to understand when and how cannabinoid systems are activated. In turn, new therapeutic strategies would likely to emerge.
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PMID:Behavioral effects of cannabinoid agents in animals. 1080 37

Understanding of cannabinoid (CB) actions has been remarkably advanced during the last decade, due mainly to the identification of the G-protein-coupled cannabinoid receptors, namely, CB1 receptors that are predominantly found in the brain and CB2 receptors that are exclusively found in peripheral tissues. Endogenous ligands for these receptors have also been identified. Research to date suggests that the analgesic effect of cannabinoids and the enhancement of opioid analgesia by cannabinoids are both CB1 receptor-mediated via the activation of opioid receptors. The involvement of the CB1 receptor in mediating reinforcing and physical dependence-producing effects of opioids has also been suggested, with the former being considered the result of interaction with the dopaminergic neurotransmission in the midbrain dopamine system. However, the discriminative stimulus effects of cannabinoids have been reported to be highly specific in that the effects were not substituted by other classes of compounds including opioidergic and dopaminergic agents nor were they antagonized by antagonists of various neurotransmission systems, suggesting that the discriminative stimulus effects only involve the cannabinoid system. Thus the cannabinoid actions appear to be classifiable into at least two kinds: 1) those mediated directly through cannabinoid receptors and 2) those mediated indirectly through other systems such as opioidergic systems. Detailed research into these actions may help to elucidate not only the mechanisms of action of exogenous cannabinoids but also the role of endogenous cannabinoids, especially in the brain reward system.
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PMID:Role of cannabinoid receptor in the brain as it relates to drug reward. 1113 22

In the present work, we investigated in the rat the possibility of functional interaction between opiate and cannabinoid systems at immune level comparatively with the central nervous system (CNS). Moderate analgesic doses of the synthetic cannabinoid compound CP-55,940 (0.2 mg/kg, i.p.) and morphine (5 mg/kg, s.c.) significantly inhibited the ConA-induced splenocyte proliferation and natural killer (NK) cytolytic activity. The acute co-administration of the two drugs resulted in an enhancement of antinociception while they did not yield any additive inhibition of the immune parameters. The CB1 cannabinoid receptor antagonist N-(Piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716A; 3 mg/kg, i.p.) and the CB2 receptor antagonist N-[(1S)-endo-1,3,3-trimethhyl bicyclo[2.2.1]heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528; 3 mg/kg, i.p.) did not block the central nor the immune effects of morphine; similarly, the opioid receptor antagonist naloxone did not attenuate CP-55,940-induced effects. Animals tolerant to CP-55,940-induced (0.2 mg/kg, i.p.; twice a day for 4 days) or morphine-induced analgesia (5 mg/kg, s.c.; twice a day for 6 days) also developed tolerance to their acute immunosuppressive effects. Concomitantly, animals became cross-resistant to the immunosuppressive effects while an asymmetric cross-tolerance developed for analgesia. Our data demonstrated the existence of an interaction between cannabinoids and opiates at the immune level that differs from the interaction present in the CNS.
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PMID:Comparative characterization in the rat of the interaction between cannabinoids and opiates for their immunosuppressive and analgesic effects. 1143 Oct 11

Cannabis occurs naturally in the dried flowering or fruiting tops of the Cannabis sativa plant. Cannabis is most often consumed by smoking marihuana. Cannabinoids are the active compounds extracted from cannabis. Recently, there has been renewed interest in cannabinoids for medicinal purposes. The two proven indications for the use of the synthetic cannabinoid (dronabinol) are chemotherapy-induced nausea and vomiting and AIDS-related anorexia. Other possible effects that may prove beneficial in the oncology population include analgesia, antitumor effect, mood elevation, muscle relaxation, and relief of insomnia. Two types of cannabinoid receptors, CB1 and CB2, have been detected. CB1 receptors are expressed mainly in the central and peripheral nervous system. CB2 receptors are found in certain nonneuronal tissues, particularly in the immune cells. Recent discovery of both the cannabinoid receptors and endocannabinoids has opened a new era in research on the pharmaceutical applications of cannabinoids. The use of cannabinoids should be continued in the areas indicated, and further studies are needed to evaluate other potential uses in clinical oncology.
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PMID:Established and potential therapeutic applications of cannabinoids in oncology. 1261 20

Cannabinoid receptor agonists produce analgesia for pains of non-cranial origin. However, their effectiveness for craniofacial pains is currently unclear. In the present study, the cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (WIN), was bath applied to the brainstem while activity of spinal trigeminal nucleus caudalis (Vc) neurons evoked by transcutaneous electrical stimulation was recorded in isoflurane anesthetized rats. Neurons were characterized using mechanical and electrical stimulation of the face, and were classified as either low-threshold mechanoreceptive (LTM) or wide dynamic range (WDR). LTM neurons responded to light brushing of the receptive field and received only Abeta primary afferent fiber input. WDR neurons showed a graded response to mechanical stimulation, responding maximally to noxious stimuli, and demonstrated both A- and C-fiber evoked activity. In addition, WDR neurons displayed longer latency, C-fiber mediated post-discharge (PDC) activity after repetitive stimulation. Local bath application of 2.0 mg/ml WIN significantly reduced PDC activity (3+/-1% control, P<0.01), C-fiber evoked activity (58+/-9% control, P<0.01), and Abeta evoked activity (57+/-10% control, P<0.01) in WDR neurons. In contrast, LTM Abeta-fiber evoked activity increased after local administration of WIN (204+/-52% control, P<0.01). SR141716A, a CB1 receptor antagonist, prevented the effects of WIN on WDR PDC and LTM Abeta evoked activity. These results indicate that cannabinoid receptor agonists may be effective agents for craniofacial pain. Furthermore, the particular sensitivity of PDC activity, a measure of neuronal hyperexcitability, to cannabinoid receptor agonists may be relevant to the treatment of persistent craniofacial pain.
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PMID:Local application of the cannabinoid receptor agonist, WIN 55,212-2, to spinal trigeminal nucleus caudalis differentially affects nociceptive and non-nociceptive neurons. 1473 89

G protein-coupled receptors (GPCRs) and their ligands play a number of important roles in the modulation of acute and chronic pain. Indeed, opioid and cannabinoid ligands are of established therapeutic value for pain management, and further exploitation of the specific GPCR subtypes (delta-opioid, CB1 and CB2) for these ligands may yield more selective, potent analgesics with favorable side effects. More recent identification of a number of other GPCRs involved in pain pathways (eg, sensory neuron specific receptors) and selective ligands that modulate pain transmission, has highlighted further therapeutic opportunities. A further challenge to understanding pain modulation and an additional dimension for targeting analgesia is the discovery of GPCR heteromerization and accessory and regulatory proteins, such as regulator of G protein-signaling proteins, involved in expression and regulation of GPCR.
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PMID:Novel G protein-coupled receptors as pain targets. 1498 76


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