Kappa opioid receptors are expressed by interneurons in the CA1 area of the rat hippocampus: a correlated light and electron microscopic immunocytochemical study.

A local GABA-system is known to have a mediatory function between several afferents and the principal cells of the hippocampus. This study examines the distribution and fine structure of kappa opioid receptor-immunoreactive elements in the CA1 subfield and reveals some new aspects concerning the structural basis of opioid-GABA interaction in the rat hippocampal formation. Kappa receptors were visualized immunocytochemically with a previously produced and characterized monoclonal antibody, the mAb KA8 (Maderspach, K.

Regulation of kappa-opioid receptor mRNA level by cyclic AMP and growth factors in cultured rat glial cells.

The mRNA of the kappa-opioid receptor (KOR) has been found recently in cultured astrocytes and in microglia. By using RT-PCR and Southern hybridization, we confirmed these observations and, in addition, we observed that KOR mRNA was expressed in oligodendrocytes and in the precursors of astrocytes and oligodendrocytes. KOR mRNA level was the highest in the immature astrocytes and decreased with their maturation.

Endogenous opioid system in developing normal and jimpy oligodendrocytes: mu and kappa opioid receptors mediate differential mitogenic and growth responses.

The early development of both neurons and neuroglia may be modulated by signaling through opioid mediated pathways. Neurons and astroglia not only express specific types of opiate receptors, but also respond functionally to opioids with altered rates of proliferation and growth. The present study was undertaken to determine if opioids also modulate development of the other major CNS macroglial cell, the oligodendrocyte (OL).

The kappa-opioid receptor is present in porcine ovaries: localization in granulosa cells.

Opioid peptides derived from several genes are present in the reproductive system and are known to be involved in the regulation of reproduction. This work shows that the level of alpha-neoendorphin which derives from prodynorphin changes in folliculogenesis. The lowest level was observed in the small follicles, increased in the medium, and reached the highest level in the preovulatory follicles.

Differential expression of the K-2 opioid receptor protein under the effect of opioid agonists in embryonic chick neurons in vitro.

Neuronal cells cultured from 7-day-old chick embryos and differentiated under the chronic effect of opioid drugs were studied for kappa-opioid receptor expression. Plasma-membrane integrated receptors were measured by radioligand ([3H]-naloxone 1 nM, [3H]-ethylketocyclazocine, 4 nM) binding to intact neurons. These data were compared to the results of k-opioid receptor immunostaining (mAb KA8, Maderspach et al.

kappa-opioid receptor expression defines a phenotypically distinct subpopulation of astroglia: relationship to Ca2+ mobilization, development, and the antiproliferative effect of opioids.

To assess the role of kappa-opioid receptors in astrocyte development, the effect of kappa-agonists on the growth of astroglia derived from 1-2-day-old mouse cerebra was examined in vitro. kappa-Opioid receptor expression was assessed immunocytochemically (using KA8 and KOR1 antibodies), as well as functionally by examining the effect of kappa-receptor activation on intracellular calcium ([Ca2+]i) homeostasis and DNA synthesis. On days 6-7, as many as 50% of the astrocytes displayed kappa-receptor (KA8) immunoreactivity or exhibited increases in [Ca2+]i in response to kappa-agonist treatment (U69,593 or U50,488H).

Cellular distribution of the mRNA for the kappa-opioid receptor in the human neocortex: a non-isotopic in situ hybridization study.

Opioid receptors (OR) provide primary interaction sites of the human brain with opiates. Presently kappa-OR mRNA expression was studied in different cortical areas (A4, A10, A17) by in situ hybridization using digoxigenin-labeled oligonucleotides and an alkaline phosphatase-mediated color reaction. kappa-OR mRNA was expressed mainly in layers II/III and V pyramidal and layer VI multiform neurons.

Expression of protein kinase C family members in the cerebral endothelial cells.

The protein kinase C (PKC) family is composed of at least four conventional (alpha, beta I, beta II, and gamma) and several related novel (delta, epsilon, eta, and zeta) isoforms with different distribution and sensitivity to Ca2+ and phorbol esters. The enzyme is known to be present in cerebral endothelial cells. We have investigated the occurrence of seven isoforms (alpha, beta, gamma, delta, epsilon, eta, and zeta) by using reverse transcriptase-polymerase chain reaction in rat brain, in a freshly isolated brain microvessel fraction, in primary cultures of rat brain endothelial cells, in an immortalized rat brain endothelial cell line, and in aortic endothelial cell cultures.

Postsynaptic and extrasynaptic localization of kappa-opioid receptor in selected brain areas of young rat and chick using an anti-receptor monoclonal antibody.

kappa-opioid receptors were visualized by light and electron microscopical immunohistochemistry in young rat and chick brains, using a monoclonal antibody KA8 (IgG1, kappa) raised against a kappa-opioid receptor preparation from frog brain, which recognizes selectively the kappa-type receptor with preference for the kappa-2 subtype. The most pronounced kappa-opioid receptor-like immunoreactivity was observed in the hypothalamic nuclei of the rat brain and in the chick optic tectum, in regions where the functional significance of kappa-opioid receptors is well documented. Both neurons and glia were stained, the former on both somata and dendrites.

Immunohistochemical localization of kappa opioid receptors in the human frontal cortex.

The cellular and subcellular kappa opioid receptor distribution in human frontal cortex was studied using the monoclonal antibody (KA8). kappa opioid receptor-like immunoreactivity was mainly localized in pyramidal neurons of layers II/III and V. In addition, some round and ovoid neurons were found immunolabeled mainly in layer VI.

Structural order of membranes and composition of phospholipids in fish brain cells during thermal acclimatization.

A comparison of the structural orders of membranes of a mixed brain-cell population isolated from Cyprinus carpio L. acclimated to either summer (23-25 degrees C) or winter (5 degrees C) revealed a high degree of compensation (80%) for temperature, as assayed by electron spin resonance spectroscopy. The cells rapidly forget their thermal history and adjust the physical properties of the membranes when shifted to the other extreme of temperature either in vivo or in vitro.

Immunocytochemical visualization of kappa-opioid receptors on chick embryonic neurons differentiating in vitro.

The present paper is the first immunocytochemical demonstration of kappa-opioid receptors in neurons isolated from seven-day-old chick embryonic forebrains and cultivated for one to seven days. The monoclonal antibody KA8 (IgG1-k) [Maderspach et al. (1991) J.

In situ hybridization with digoxigenin labeled oligonucleotide probes: detection of CAMK-II gene expression in primary cultures of cerebral endothelial cells.

A better understanding of the regulation of gene expression under physiological and experimental conditions is one of the most important goals of today's neurobiology. In order to accomplish this task a number of in-situ hybridization methods have been elaborated. In the past few years the use of nonradioactive procedures have gained more and more space among these efforts.

A monoclonal antibody recognizing kappa- but not mu- and delta-opioid receptors.

A monoclonal antibody (mAb), KA8 that interacts with the kappa-opioid receptor binding site was generated. BALB/c female mice were immunized with a partially purified kappa-opioid receptor preparation from frog brain. Spleen cells were hybridized with SP2/0AG8 myeloma cells.

Glial and neuronal opioid receptors: apparent positive cooperativity observed in intact cultured cells.

Opioid receptors were characterized in glial and neuronal homogeneous cultures of embryonic chick forebrain, using [3H]naloxone as a labelled ligand. Binding experiments were performed on intact cells. The specific binding of [3H]naloxone reached equilibrium after 1 min.

GABAA receptor-controlled 36Cl- influx in cultured rat cerebellar granule cells.

gamma-Aminobutyric acid (GABA)-mediated and bicuculline-sensitive 36Cl- influx and bicuculline-sensitive [3H] GABA binding were demonstrated in cultures of rat cerebellar granule cells. The addition of 10(-5) M GABA produced a two-fold increase in 36Cl-influx over the basal level and the maximal increase was observed after approximately 20 sec. Progressive occupation of GABAA receptor by [3H]-(1S-9R)-bicuculline methiodide decreased 36Cl- influx activated by 10 microM GABA.

Towards a more physiological approach in GABA binding.

Gamma-aminobutyric acid (GABA) mediates the postsynaptic inhibition via reversible binding to specific recognition (receptor) sites. Despite extensive research, the results from binding and functional response measurements remains controversial. It is suggested that controversies may partly result from the use of non-physiological buffer during the preparation and binding assay of the GABA receptor.

Development of beta-adrenergic receptors and their function in glia-neuron communication in cultured chick brain.

The beta-receptors of intact neuronal and glial cells of chick embryonic brain were studied via the specific binding of the beta-antagonist [3H]dihydro-L-alprenolol ( [3H]DHA). Cells were cultivated in either highly homogeneous or mixed populations; the neuronal cells were also grown under the influence of glial conditioned medium (GCM) or 10(-11)-10(-10) M L-norepinephrine or L-isoproterenol. The beta-receptors of both neuronal and glial cells proved to be positively cooperative (n = 2.

beta-Adrenergic receptors of brain cells. Membrane integrity implies apparent positive cooperativity and higher affinity.

Beta-Adrenergic receptors were studied in intact cells of chick, rat and mouse embryo brain in primary cultures, by the specific binding of [3H]dihydro-L-alprenolol ([3H]DHA). The results were compared to the receptor binding of broken cell preparations derived from the cell cultures or from the forebrain tissues used for the preparation of the cultures. Detailed analysis of [3H]DHA binding to living chick brain cells revealed a high-affinity, stereoselective, beta-adrenergic-type binding site.

Muscarinic acetylcholine receptors on culture glia cells.

Muscarinic acetylcholine receptors (76 fmol/mg protein) were detected on cultured glia cells (astroblasts) from embryonic chicken brain by specific [3H]quinuclidinylbenzilate (QNB) binding at physiological conditions. The QNB binding (Kd = 9.5 x 10(-11)) to the intact cells seems to be cooperative (nH = 1.

Binding of fluorescent and radiolabelled alprenolol to intact cultured brain cells and liposomes.

Beta-adrenergic antagonist L-alprenolol was labelled for radioactivity and UV fluorescence, and the binding to intact cultured chicken brain cells under equilibrium conditions, as the model of the experiments in vivo, was probed. The application of fluorescent label did not explore any cell type or cell particle with enhanced binding. The analysis of the radiolabelled alprenolol-binding revealed a non-specific accumulation on the surface of these cells, which was inhibited by unlabelled alprenolol excess, however, this is the peculiarity of the specific binding.

Neuronal cells from chick embryo cerebral hemispheres cultivated on polylysine-coated surfaces.

Dissociated cells from 5- to 12-day-old chick embryo cerebral hemispheres were cultivated in polylysine-coated plastic Petri dishes. The polylysine substrate was observed to be favorable for the growth of neuronal cells, whereas glioblast proliferation was inhibited. The optimal conditions for the production of a predominantly neuronal culture were to use cerebral hemispheres from 7-day-old chick embryos, to dissociate the brain tissue mechanically and to seed the cells at a concentration range between 1.

A comparative study of the differentiation of dissociated nerve cells under different culture conditions.

In vitro differentiation of chick embryo brain cells was compared under several culture conditions. Morphological observations and acetylcholinesterase histochemical staining revealed that the development was similar in all conditions tested if cells have been derived from 7 days embryos. Considering the cultures from 11 days embryos, the cell dissociation by trypsin and the plastic surface proved to be the most favourable conditions in contrast to mechanical dissection and collagen surface.