Opioid and Opiate Immunoregulatory Processes.

The discovery of the ability of the nervous system to communicate through "public" circuits with other systems of the body is attributed to Ernst and Berta Scharrer, who described the neurosecretory process in 1928. Indeed, the immune system has been identified as another important neuroendocrine target tissue. Opioid peptides are involved in this communication (i.

Modulation of agonist stimulated adenylyl cyclase and GTPase activity by L-pro-L-leu-glycinamide and its peptidomimetic analogue in rat striatal membranes.

L-prolyl-L-leucyl-glycinamide (PLG), also known as melanocyte-stimulating hormone release inhibiting factor (MIF-1), is an endogenous brain tripeptide. Previous studies have shown that PLG, and its peptidomimetic analogues, render dopamine D2 receptors more responsive to agonists by maintaining the high-affinity binding state of the receptors. In the present study, we examined the effect PLG and its analogue 3(R)-[(2(S)-pyrrolidylcarbonyl)amino]-2-oxo-1-pyrrolidineacetam ide (PAOPA) on dopamine-stimulated adenylyl cyclase and NPA-stimulated GTPase activity in rat striatal membranes.

Properties of mu 3 opiate alkaloid receptors in macrophages, astrocytes, and HL-60 human promyelocytic leukemia cells.

An opiate alkaloid-selective receptor, designated mu(3), mediates inhibition by morphine of activation of human peripheral blood monocytes and granulocytes. The mu(3) receptor is present on several macrophage cell types including microglia, on cultured astrocytes, and in brain and retina. Murine macrophage cell lines and human HL-60 leukemia cells contain high concentrations of these receptors.

Presence of nociceptin (orphanin FQ) receptors in rat retina: comparison with receptors in striatum.

Nociceptin (orphanin FQ), a heptadecapeptide with some sequence homology to dynorphin A, has been proposed as an endogenous ligand for a previously cloned orphan receptor with significant homology to opioid receptors. Utilizing [(125)I][Tyr14]nociceptin as ligand, saturable and high affinity nociceptin binding sites were detected and characterized in rat retina and striatum. For retina, Bmax = 44.

Presence and characterization of nociceptin (orphanin FQ) receptor binding in adult rat and human fetal hypothalamus.

High affinity and saturable nociceptin (orphanin FQ) receptors were detected and characterized in adult rat and human fetal hypothalamic membranes, utilizing [125I]Tyr12-nociceptin as ligand. Nociceptin bound with picomolar affinity, dynorphin A with nanomolar affinity, naloxone and dynorphan A(1-8) with micromolar while des-Tyr1-dynorphin (dynorphin A(2-17)), several other opioids, morphine and benzomorphans failed to compete for binding at 1-10 microM. Gpp(NH)p together with sodium ion markedly decreased binding, consistent with involvement of a G protein-linked receptor.