Distribution Of Leu-enkephalin Research Articles

Distribution of leucine-enkephalin in bone and joint tissues

The distribution and concentration of leu-enkephalin in periosteum, cortical bone, bone marrow and synovial membrane of normal rats were analysed. Periosteum, cortical bone and bone marrow of the rat femurs were collected as well as the ankles. The distribution of leu-enkephalin was analysed by immunoelectron microscopy and the concentration of leu-enkephalin was measured with radioimmunoassay. Immunoelectron microscopy showed that leu-enkephalin is abundant in monocytes of bone marrow, nerve fibers and endothelial cells in the periosteum and also in macrophage-like-cells of the synovial membrane. The concentration of leu-enkephlin measured by RIA showed highest concentration in bone marrow followed by periosteum and cortical bone. The study supports that leu-enkephalin is present and can be quantified in different compartments of bone and joint tissues suggesting that leu-enkephalin may be involved in the physiological regulation of nociception and immunoregulation.

Immunohistochemical localization of serotoninergic, enkephalinergic, and catecholaminergic cells in the brainstem and diencephalon of a cartilaginous fish, hydrolagus colliei

We localized serotonin (5-HT), leu-enkephalin (LENK), and tyrosine hydroxylase (TH) immunoreactive cells in the brain of a holocephalian, Hydrolagus colliei, by use of antibodies made in rabbit and the peroxidase-antiperoxidase technique. Only three locations contained TH+ cells, the caudal myelencephalon, the locus coeruleus, and the diencephalon. Of these locations, the diencephalon contained the most cells and the locus coeruleus the least cells. The caudal TH+ myelencephalic cells formed a single large group that spanned both the dorsal and ventral portions of the brain (A1A2). The diencephalic TH+ cells were located in the posterior tuberculum, in the ventromedial and ventrolateral thalamic nuclei, and in the inferior lobe of the hypothalamus. Hydrolagus differed from mammals and the elasmobranchs, their sister group, in that no substantia nigra (A9), ventral tegmental area (A10), or A5 cell group was found. Distribution of LENK+ and 5-HT+ cells were similar to each other; the raphe nuclei contained most of the 5-HT+ and LENK+ cells. These 5-HT+ and LENK+ cells were found at all rostrocaudal levels of the myelencephalon. The nucleus reticularis magnocellularis, reticularis paragigantocellularis lateralis, the ventral met- and mesencephalon (B7 and B9 cell groups), the hypothalamus, and the pretectal area contained additional 5-HT+ and LENK+ cells. The solitary complex contained LENK+ cells but not but 5-HT+ cells. A dorsal raphe nucleus, which is the largest 5-HT+ cell group in mammals, was absent in Hydrolagus. A dorsal raphe nucleus is present in one galeomorph shark radiation but is absent in three radiations of batoids (rays, skates, and guitarfish). Thus even within cartilaginous fish, there are differences in the distribution of neurochemicals and possibly nuclei within their brains.

Substance P and enkephalins in the superficial layers of the rat superior colliculus: Differential plastic effects of retinal deafferentation

In this work we studied the effects of unilateral eye enucleation on the contents and distribution of leu-enkephalin-, met-enkephalin-arg6-gly7-leu8-, and substance-P-like immunoreactivities (L-ENK-I, ENK-8-I, and SP-I, respectively) in the superficial layers of the rat superior colliculus (SC) by means of the unlabelled antibody peroxidase-antiperoxidase method. In the normal rat only a few L-ENK-I neurons appear dispersed in the stratum griseum superficiale. No immunostained somata appear in the stratum opticum. The most striking effect of unilateral enucleation was the dramatic appearance of a laminarly distributed population of L-ENK-I and/or ENK-8-I neurons in the dorsal stratum opticum of the SC contralateral to the enucleated side. This population of immunoreactive cells was observed with all the survival times examined in the present study (3, 7, 15, and 30 days) and was always accompanied by an increase in the immunostaining of L-ENK-I and/or ENK-8-I fibers in the contralateral stratum griseum superficiale. Enucleation also produced a decrease in the immunostaining of SP-I dendrites that only became obvious 15 days after enucleation. However, the number of SP-I somata or terminal-like immunoreactive structures showed no detectable changes. These results show that retinal deafferentation of the superficial layers of the rat SC has different effects on some immunohistochemically distinguishable neuronal subgroups in the SC, suggesting different functional or trophic relationships of the retinal input to these groups of neurons.