Hemopressin as a breakthrough for the cannabinoid field.

Hemopressin (PVNFKFLSH in rats, and PVNFKLLSH in humans and mice), a fragment derived from the α-chain of hemoglobin, was the first peptide described to have type 1 cannabinoid receptor activity. While hemopressin was shown to have inverse agonist/antagonistic activity, extended forms of hemopressin (i.e.

Capsaicin inhibits lipopolysaccharide-induced adrenal steroidogenesis by raising intracellular calcium levels.

Introduction: Glucocorticoid release by adrenals has been described as significant to survive sepsis. The activation of transient receptor potential vanilloid type 1 (TRPV1) inhibited ACTH-induced glucocorticoid release by adrenal glands in vitro.

Objective: The aim of this study was to investigate if capsaicin, an activator of TRPV1, would prevent LPS-induced glucocorticoid production by adrenals.

Experimental ischemia/reperfusion model impairs endocannabinoid signaling and Na/K ATPase expression and activity in kidney proximal tubule cells.

LLC-PK1 cells, an immortalized epithelial cell line derived from pig renal proximal tubules, express all the major players of the endocannabinoid system (ECS) such as CB1, CB2 and TRPV1 receptors, as well as the main enzymes involved in the biosynthesis and degradation of the major endocannabinoids named 2-arachidonoylglycerol, 2-AG and anandamide, AEA. Here we investigated whether the damages caused by ischemic insults either in vitro using LLC-PK1 cells exposed to antimycin A (an inductor of ATP-depletion) or in vivo using Wistar rats in a classic renal ischemia and reperfusion (IR) protocol, lead to changes in AEA and 2-AG levels, as well as altered expression of genes from the main enzymes involved in the regulation of the ECS. Our data show that the mRNA levels of the CB1 receptor gene were downregulated, while the transcript levels of monoacylglycerol lipase (MAGL), the main 2-AG degradative enzyme, were upregulated in LLC-PK1 cells after IR model.

Neuro-glial cannabinoid receptors modulate signaling in the embryonic avian retina.

Endocannabinoids are endogenous lipids that activate selective G protein coupled receptors (CB and CB), mostly found at neuronal presynaptic sites in the nervous system. One of the main consequences of the activation of CB receptors is a decrease in GABA or glutamate release, controlling cell excitability. Here we studied the expression of CB and CB receptors in E8C8 cultured retina cells (embryonic day 8 and 8 days in vitro) using immunocytochemistry and western blot analysis.

P2X7 receptor large pore signaling in avian Müller glial cells.

ATP is a pleiotropic molecule that promotes extra- and intracellular signaling to regulate numerous functions. This nucleotide activates purine and pyrimidine receptors at the plasma membrane, categorized as ionotropic P2X or G-protein-coupled receptor (GPCR) P2Y receptors. P2X are ligand-gated ion channel receptors, expressed in both retinal neurons and Müller cells leading to neuron-glia communication, calcium waves and neurovascular coupling.

P2X7R large pore is partially blocked by pore forming proteins antagonists in astrocytes.

The ATP-gated P2X7R (P2X7R) is a channel, which is involved in events, such as inflammation, cell death, and pain. The most intriguing event concerning P2X7R functions is the phenomenon of pore dilation. Once P2X7R is activated, the permeability of the plasma membrane becomes higher, leading to the permeation of 1000 Da-weight solutes.

Functional plasticity of GAT-3 in avian Müller cells is regulated by neurons via a glutamatergic input.

GABA (γ-amino butyric acid) is the major inhibitory transmitter in the central nervous system and its action is terminated by specific transporters (GAT), found in neurons and glial cells. We have previously described that GAT-3 is responsible for GABA uptake activity in cultured avian Müller cells and that it operates in a Na(+) and Cl(-) dependent manner. Here we show that glutamate decreases [(3)H] GABA uptake in purified cultured glial cells up to 50%, without causing cell death.

Bone marrow-derived fibroblast growth factor-2 induces glial cell proliferation in the regenerating peripheral nervous system.

Background: Among the essential biological roles of bone marrow-derived cells, secretion of many soluble factors is included and these small molecules can act upon specific receptors present in many tissues including the nervous system. Some of the released molecules can induce proliferation of Schwann cells (SC), satellite cells and lumbar spinal cord astrocytes during early steps of regeneration in a rat model of sciatic nerve transection. These are the major glial cell types that support neuronal survival and axonal growth following peripheral nerve injury.

Secreted human amyloid precursor protein binds semaphorin 3a and prevents semaphorin-induced growth cone collapse.

The amyloid precursor protein (APP) is well known for giving rise to the amyloid-β peptide and for its role in Alzheimer's disease. Much less is known, however, on the physiological roles of APP in the development and plasticity of the central nervous system. We have used phage display of a peptide library to identify high-affinity ligands of purified recombinant human sAPPα(695) (the soluble, secreted ectodomain from the main neuronal APP isoform).

Expression of functional dopaminergic phenotype in purified cultured Müller cells from vertebrate retina.

Purified retina glial Müller cells can express the machinery for dopamine synthesis and release when maintained in culture. Dopamine is detected in cell extracts of cultures exposed to its precursor, L-DOPA. A large portion of synthesized dopamine is recovered in the superfusing medium showing the tendency of the accumulated dopamine to be released.

Dopaminergic signaling in the developing retina.

The role of dopamine in the retina has been studied for the last 30 years and there is now increasing evidence that dopamine is used as a developmental signal in the embryonic retina. Dopamine is the main catecholamine found in the retina of most species, being synthesized from the L-amino acid tyrosine. Its effects are mediated by G protein coupled receptors constituting the D(1) (D(1) and D(5)) and D(2) (D(2), D(3) and D(4)) receptor subfamilies that can be coupled to adenylyl cyclase in opposite manners.

Regulation of acetylcholine synthesis and storage.

Acetylcholine is one of the major modulators of brain functions and it is the main neurotransmitter at the peripheral nervous system. Modulation of acetylcholine release is crucial for nervous system function. Moreover, dysfunction of cholinergic transmission has been linked to a number of pathological conditions.

Sympathetic neuronal survival induced by retinal trophic factors.

Neuronal survival in the vertebrate peripheral nervous system depends on neurotrophic factors available from target tissues. In an attempt to identify novel survival factors, we have studied the effect of secreted factors from retinal cells on the survival of chick sympathetic ganglion neurons. Embryonic day 10 sympathetic neurons undergo programmed cell death after 48 h without appropriate levels of nerve growth factor (NGF).