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)

1. Effects of cannabinoid agonists on the serotonin (5-HT)3 receptor-mediated current were investigated in rat nodose ganglion neurons. Anandamide, Win 55212-2, and CP55940 inhibited the 5-HT-induced current in a concentration dependent manner. IC50 values were 190, 310, and 94 nM for anandamide, Win 55212-2, and CP55940, respectively, and 1.6 microM for the nonpsychoactive enantiomer CP56667. This inhibition was slowly developing, noncompetitive, not dependent on membrane potential, and not affected by adenosine 3',5'-cyclic monophosphate (cAMP) analogues, guanosine-5'-O-(2-thiodiphosphate) (GDP-beta-S), and opioid receptor antagonist naltrexone. These data suggest that 5-HT3 receptor ion-channel is a site acted upon by cannabinoid agonists in the nervous system, and the action of cannabinoid agonists on 5-HT3 receptors may be a possible mechanism for some of the behavioral effects of cannabinoids, such as antiemesis and analgesia.
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PMID:Cannabinoid agonists inhibit the activation of 5-HT3 receptors in rat nodose ganglion neurons. 776 Jan 48

Anandamide (arachidonylethanolamide) is a brain constituent which binds to the cannabinoid receptor. We now report the first in vivo examination of this ligand. Anandamide administered i.p. in mice, caused lowering of activity in an immobility and in an open field test, and produced hypothermia and analgesia. These effects parallel those caused by psychotropic cannabinoids.
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PMID:Pharmacological activity of the cannabinoid receptor agonist, anandamide, a brain constituent. 838 16

Effects of the endogenous cannabimimetic anandamide were assessed over a wide dose range in a series of physiological and behavioral assays. These included the tetrad of tests in mice commonly used to assess cannabinoid-induced effects (motor activity, ring catalepsy, hypothermia, and analgesia tests), as well as a model for agonistic behavior on dyadic interactions of singly housed males with nonaggressive group-housed partners. Anandamide-induced effects on leukocyte phagocytosis were measured in a chemiluminescence assay. Results indicated that the higher doses tested (10-100 mg/kg) produced the well-known inhibitory effects in all of the above parameters as well as inhibition of phagocytosis. The lowest dose of anandamide tested (0.01 mg/kg) stimulated behavioral activities in the open field, on the ring and aggressive behavior in timid singly housed mice. This dose of 0.01 mg/kg, also stimulated phagocytosis. We suggest several possible mechanisms to explain these findings such as a differential involvement of a Gs and a Gi protein activated at low and high doses, respectively, allosteric modulation of the cannabinoid, and activation of presynaptic cannabinoid receptors by low doses of anandamide.
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PMID:Biphasic effects of anandamide. 947 80

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

Anandamide [arachidonylethanolamide (AEA)] appears to be an endogenous agonist of brain cannabinoid receptors (CB(1)), yet some of the neurobehavioral effects of this compound in mice are unaffected by a selective CB(1) antagonist. We studied the levels, pharmacological actions, and degradation of AEA in transgenic mice lacking the CB(1) gene. We quantified AEA and the other endocannabinoid, 2-arachidonoyl glycerol, in six brain regions and the spinal cord by isotope-dilution liquid chromatography-mass spectrometry. The distribution of endocannabinoids and their inactivating enzyme, fatty acid amide hydrolase, were found to overlap with CB(1) distribution only in part. In CB(1) knockout homozygotes (CB(1)-/-), the hippocampus and, to a lesser extent, the striatum exhibited lower AEA levels as compared with wild-type (CB(1)+/+) controls. These data suggest a ligand/receptor relationship between AEA and CB(1) in these two brain regions, where tonic activation of the receptor may tightly regulate the biosynthesis of its endogenous ligand. 2-Arachidonoyl glycerol levels and fatty acid amide hydrolase activity were unchanged in CB(1)-/- with respect to CB(1)+/+ mice in all regions. AEA and Delta(9)-tetrahydrocannabinol (THC) were tested in CB(1)-/- mice for their capability of inducing analgesia and catalepsy and decreasing spontaneous activity. The effects of AEA, unlike THC, were not decreased in CB(1)-/- mice. AEA, but not THC, stimulated GTPgammaS binding in brain membranes from CB(1)-/- mice, and this stimulation was insensitive to CB(1) and CB(2) antagonists. We suggest that non-CB(1), non-CB(2) G protein-coupled receptors might mediate in mice some of the neuro-behavioral actions of AEA.
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PMID:Levels, metabolism, and pharmacological activity of anandamide in CB(1) cannabinoid receptor knockout mice: evidence for non-CB(1), non-CB(2) receptor-mediated actions of anandamide in mouse brain. 1108 Jan 95

Stearoylethanolamide (SEA) is present in human, rat, and mouse brain in amounts comparable to those of the endocannabinoid anandamide (arachidonoylethanolamide, AEA). Yet, the biological activity of SEA has never been investigated. We report that SEA has the same effects as AEA on catalepsy, motility, analgesia, and body temperature of mice and that specific binding sites for SEA are present in mouse brain and are most abundant in cortex. Pharmacological experiments and the use of knockout mice demonstrated that these sites are different from cannabinoid receptors, are not coupled to G proteins, and regulate different signaling pathways. Mouse brain has also a specific SEA membrane transporter and a fatty acid amide hydrolase able to cleave SEA, with the same regional distribution as the binding sites of this lipid. Moreover, SEA potentiates the decrease of cAMP induced by AEA in mouse cortical slices, suggesting that SEA might also be an "entourage" compound.
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PMID:Cannabimimetic activity, binding, and degradation of stearoylethanolamide within the mouse central nervous system. 1235 56

The endogenous cannabinoid anandamide, a lipid mediator, induces various physiologic events such as vascular relaxation, inhibition of gap-junctions formation, tumor proliferation, neurologic analgesia, and apoptosis. Although increased concentration of anandamide in plasma has been implicated in pathophysiologic states including endotoxin-induced hypotension, the effects of anandamide on hepatocytes still remain unclear. In this study, we present evidence that plasma anandamide concentration is highly increased in severe hepatitis and cirrhosis patients. In addition, concentrations of anandamide within the pathophysiologic range potently induced apoptosis of hepatoma cell line (Hep G2) and primary hepatocytes, suggesting a possible link between increased anandamide level and hepatocyte damage. Anandamide-induced cell death was preceded by G0/G1 cell-cycle arrest, activation of proapoptotic signaling (i.e., p38 MAPK and JNK), and inhibition of antiapoptotic signaling (i.e., PKB/Akt) pathways. Moreover, anandamide increased susceptibility to oxidative stress-induced hepatocyte damage. In this context, methyl-beta-cyclodextrin (MCD), a membrane cholesterol depletor, or mevastatin, an HMG-CoA reductase inhibitor, or N-acetyl cysteine, an antioxidant, potently inhibited the anandamide-induced proapoptotic events and cell death, whereas putative cannabinoid receptor antagonists did not exhibit an inhibitory effect on anandamide-induced cell death. Furthermore, binding assay using polymyxin beads revealed that anandamide could interact with cholesterol. In conclusion, our data suggest that cholesterol present in the cell membrane determines the fate of hepatocytes exposed to anandamide, possibly functioning as an anandamide receptor.
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PMID:Membrane cholesterol but not putative receptors mediates anandamide-induced hepatocyte apoptosis. 1457 55

Endogenous cannabinoids activate cannabinoid receptors in the brain and elicit mood-altering effects. Parallel effects (eg, anxiolysis, analgesia, sedation) may be elicited by osteopathic manipulative treatment (OMT), and previous research has shown that the endorphin system is not responsible for OMT's mood-altering effects. The authors investigate whether OMT generated cannabimimetic effects for 31 healthy subjects in a dual-blind, randomized controlled trial that measured changes in subjects' scores on the 67-item Drug Reaction Scale (DRS). Chemical ionization gas chromatography and mass spectrometry were also used to determine changes in serum levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), and oleylethanolamide (OEA). In subjects receiving OMT, posttreatment DRS scores increased significantly for the cannabimimetic descriptors good, high, hungry, light-headed, and stoned, with significant score decreases for the descriptors inhibited, sober, and uncomfortable. Mean posttreatment AEA levels (8.01 pmol/mL) increased 168% over pretreatment levels (2.99 pmol/mL), mean OEA levels decreased 27%, and no changes occurred in 2-AG levels in the group receiving OMT. Subjects in the sham manipulative treatment group recorded mixed DRS responses, with both increases and decreases in scores for cannabimimetic and noncannabimimetic descriptors and no changes in sera levels. When changes in serum AEA were correlated with changes in subjects' DRS scores, increased AEA correlated best with an increase for the descriptors cold and rational, and decreased sensations for the descriptors bad, paranoid, and warm. The authors propose that healing modalities popularly associated with changes in the endorphin system, such as OMT, may actually be mediated by the endocannabinoid system.
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PMID:Cannabimimetic effects of osteopathic manipulative treatment. 1712 26

Anandamide, the ethanolamide of arachidonic acid, is an endogenous cannabinoid. It is an agonist at CB1 and CB2 cannabinoid receptors as well as the vanilloid receptor, VR1. It is analgesic in inflammatory and neuropathic pain. Both central and peripheral mechanisms are considered to participate in its analgesia. Primary sensory neurons express Na+ currents that are involved in the pathogenesis of pain. We examined the effect of anandamide on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na+ currents in rat dorsal root ganglion neurons. Anandamide inhibited both Na+ currents in a concentration-dependent manner. At a membrane potential of -80 mV, the current inhibition was greater in TTX-S than TTX-R currents (K(d); 5.4 microM vs. 38.4 microM). The activation and inactivation became faster in TTX-R current but not in TTX-S current. Anandamide did not alter the activation voltage in either type of current. It, however, produced a hyperpolarizing shift of the steady-state inactivation voltage in both types of currents. The maximum availability at a large negative potential was not reduced by anandamide. Thus, anandamide seems to affect inactivated Na+ channels rather than resting channels. The inhibition of Na+ currents was not reversed by AM 251 (a CB1 antagonist), AM 630 (a CB2 antagonist) or capsazepine (a VR1 antagonist), suggestive of a direct action of anandamide on Na+ channels. The inhibition of Na+ currents in sensory neurons may contribute to the anandamide analgesia.
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PMID:Anandamide suppression of Na+ currents in rat dorsal root ganglion neurons. 1625 60

We previously reported that the compound O-2093 is a selective inhibitor of the reuptake of the endocannabinoid anandamide (AEA). We have now re-examined the activity of O-2093 in vivo and synthesized four structural analogs (O-2247, O-2248, O-3246, and O-3262), whose activity was assessed in: (a) binding assays carried out with membranes from cells overexpressing the human CB(1) and CB(2) receptors; (b) assays of transient receptor potential of the vanilloid type-1 (TRPV1) channel functional activity (measurement of [Ca(2+)](i)); (c) [(14)C]AEA cellular uptake and hydrolysis assays in rat basophilic leukaemia (RBL-2H3) cells; (d) the mouse 'tetrad' tests (analgesia on a hot plate, immobility on a 'ring', rectal hypothermia and hypolocomotion in an open field); and (e) the limb spasticity test in chronic relapsing experimental allergic encephalomyelitis (CREAE) mice, a model of multiple sclerosis (MS). O-2093, either synthesized by us or commercially available, was inactive in the 'tetrad' up to a 20 mg kg(-1) dose (i.v.). Like O-2093, the other four compounds exhibited low affinity in CB(1) (K(i) from 1.3 to >10 microM) and CB(2) binding assays (1.3<K(i)< 8 microM), low potency and efficacy in a TRPV1 functional assay (EC(50)>10 microM), very low potency as fatty acid amide hydrolase (FAAH) inhibitors (IC(50)>25 microM) and were inactive in the 'tetrad' up to a 30 mg kg(-1) dose (i.v.). While O-2247 and O-2248 were poor inhibitors of [(14)C]AEA cellular uptake (IC(50)>40 microM), O-3246 and O-3262 were quite potent in this assay. O-3246, which exhibits only a very subtle structural difference with O-2093, is the most potent inhibitor of AEA uptake reported in vitro under our experimental conditions (IC(50)=1.4 microM) and is 12-fold more potent than O-2093. When injected intravenously O-3246 and O-3262, again like O-2093 and unlike O-2247 and O-2248, significantly inhibited limb spasticity in mice with CREAE. These data confirm the potential utility of selective AEA uptake inhibitors as anti-spasticity drugs in MS and, given the very subtle chemical differences between potent and weak inhibitors of uptake, support further the existence of a specific mechanism for this process.
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PMID:New potent and selective inhibitors of anandamide reuptake with antispastic activity in a mouse model of multiple sclerosis. 1628 31


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