dizocilpine-maleate and glyceryl-2-arachidonate

The involvement of the endocannabinoid system in the brain functions is likely the conclusion of its capability to interact with specific neurotransmitters in several brain regions. The present study was designed to examine the role of the glutamatergic system on cannabinoid-induced hyperphagia in chicken. In this survey 10 experiments designed to investigate interaction of cannabinoidergic and glutamatergic systems on feeding behavior in neonatal chickens. In experiment 1, chicken were intracerebroventricular (ICV) injected with saline, 2-AG (2-Arachidonoylglycerol, 5.28 nmol, CB1 receptors agonist), MK-801(NMDA receptor antagonist, 15 nmol) and co-administration of 2-AG + MK-801. In experiment 2, injection of saline, 2-AG (5.28 nmol), CNQX) AMPA/kainate receptor antagonist, 390 nmol) and their combination (2-AG + CNQX) was done. In Experiment 3, injections were saline, 2-AG (5.28 nmol), AIDA)mGluR1 antagonist, 2 nmol) and 2-AG + AIDA. Experiments 4 and 5 were similar to experiment 3, except birds injected with LY341495 (mGLUR2 glutamate antagonist, 150 nmol) and UBP1112 (mGLUR3 glutamate antagonist, 2 nmol) instead of AIDA. Experiments 6-10 followed the procedure similar to experiments 1-5, except chickens received ICV injection of CB65 (CB2 receptor agonist, 3 nmol), instead of 2-AG. Then the cumulative food intake measured until 120 min post injection. According to the results, ICV injection of 2-AG and CB65 significantly increased food intake (P < 0.001). Co-injection of 2-AG and MK-801 significantly amplified hyperphagic effect of CB1 receptors agonist(P < 0.001). Moreover, co-administration of CB65 plus CNQX significantly increased CB65- induced hyperphagia in FD3 neonatal layer-type chickens (P < 0.001). These results suggest there is an interaction between endocannabinoids and glutamatergic systems via NMDA and AMPA receptors in feeding behavior of neonatal layer-type chickens.

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Animals; Animals, Newborn; Arachidonic Acids; Cannabinoid Receptor Agonists; Cannabinoids; Chickens; Dizocilpine Maleate; Eating; Endocannabinoids; Excitatory Amino Acid Antagonists; Feeding Behavior; Glutamic Acid; Glycerides; Protein Binding; Receptors, AMPA; Receptors, N-Methyl-D-Aspartate

Endogenous cannabinoid receptor ligands (endocannabinoids) may rescue neurons from glutamate excitotoxicity. As these substances also accumulate in cultured immature neurons following neuronal damage, elevated endocannabinoid concentrations may be interpreted as a putative neuroprotective response. However, it is not known how glutamatergic insults affect in vivo endocannabinoid homeostasis, i.e. N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), as well as other constituents of their lipid families, N-acylethanolamines (NAEs) and 2-monoacylglycerols (2-MAGs), respectively. Here we employed three in vivo neonatal rat models characterized by widespread neurodegeneration as a consequence of altered glutamatergic neurotransmission and assessed changes in endocannabinoid homeostasis. A 46-fold increase of cortical NAE concentrations (anandamide, 13-fold) was noted 24 h after intracerebral NMDA injection, while less severe insults triggered by mild concussive head trauma or NMDA receptor blockade produced a less pronounced NAE accumulation. By contrast, levels of 2-AG and other 2-MAGs were virtually unaffected by the insults employed, rendering it likely that key enzymes in biosynthetic pathways of the two different endocannabinoid structures are not equally associated to intracellular events that cause neuronal damage in vivo. Analysis of cannabinoid CB(1) receptor mRNA expression and binding capacity revealed that cortical subfields exhibited an up-regulation of these parameters following mild concussive head trauma and exposure to NMDA receptor blockade. This may suggest that mild to moderate brain injury may trigger elevated endocannabinoid activity via concomitant increase of anandamide levels, but not 2-AG, and CB(1) receptor density.

Topics: Animals; Arachidonic Acids; Brain Concussion; Cannabinoid Receptor Modulators; Cerebral Cortex; Corpus Striatum; Craniocerebral Trauma; Dizocilpine Maleate; Endocannabinoids; Ethanolamines; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Glycerides; Male; N-Methylaspartate; Nerve Degeneration; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Receptors, Drug; RNA, Messenger

The endogenous cannabinoids (endocannabinoids) anandamide and 2-arachidonylglycerol increased cell viability in cerebral cortical neuron cultures subjected to 8 h of hypoxia and glucose deprivation. This effect was observed at nanomolar concentrations, was reproduced by a non-hydrolyzable analog of anandamide, and was unaltered by CB1 or CB2 cannabinoid receptor antagonists. Like synthetic cannabinoids, endocannabinoids can protect neurons from hypoxic injury, and may represent endogenous neuroprotective molecules in cerebral ischemia.

Topics: Animals; Arachidonic Acids; Brain Ischemia; Cannabinoid Receptor Modulators; Cannabinoids; Cell Hypoxia; Cell Survival; Cells, Cultured; Cerebral Cortex; Dizocilpine Maleate; Endocannabinoids; Excitatory Amino Acid Antagonists; Glycerides; Neurons; Neuroprotective Agents; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley