Evidence that GYKI 52466, a novel non-NMDA antagonist enhances the decay of kainate-induced current in cultured chicken cortical neurons.

The effect of a novel non-competitive non-NMDA glutamate receptor antagonist, GYKI 52466 was studied on the glutamate agonist-induced currents in one month old cultured embryonal chicken brain neurons by a whole cell patch-clamp technique. AMPA, applied in different concentrations (30-1000 microM) did not evoke any current. Kainate evoked an increase of steady-state current (KA-current).

Pathological and experimental investigations in a case of gigantism.

A pituitary adenoma was transsphenoidally removed from a 4.5-year-old girl suffering from gigantism. Prior to the operation both the growth hormone (GH) and the prolactin (PRL) levels in the serum were elevated.

Influence of oligopeptide aldehydes on intracellular Ca2+ concentration in rat pituitary cells.

We investigated the effects of some synthetic tripeptide aldehydes, earlier shown to influence pituitary hormone secretion and 45Ca2+ uptake, on the intracellular free Ca2+ concentration ([Ca2+]i) of rat anterior pituitary cells in suspension. Boc-D-Phe-Leu-Phenylalaninal or Boc-D-Phe-Leu-Prolinal in the tested range of 1-100 or 200 microM, respectively, were ineffective in influencing basal [Ca2+]i but caused a concentration-dependent inhibition in K+ (25 mM)-induced [Ca2+]i elevation. The IC50 of both effects was about 50 microM.

Morphological and functional characterization of cell cultures from adult human adenohypophyses.

Parallel primary cultures have been prepared from dispersed cells of adult human pituitary anterior lobes and can be used as a model system for cell-biological studies. The cultured cells were able to secrete all the known hormones of the adenohypophysis. Bromocriptine administration markedly reduced prolactin release into the medium while slightly enhanced growth hormone release.

Early and late hormonal modulation of cholinergic maturation in culture of embryonic mesencephali.

Dissociated cells from 13- and 17-day-old embryonic rat mesencephali have grown in primary cultures in order to compare the early and late influences of different agents--insulin, dexamethasone and nerve growth factor (NGF)--on the expression of cholinergic maturation process. We have studied cholin acetyltransferase (ChAT) activity, which is regarded as a specific marker for cholinergic function of the brain, and a widely used differentiation marker, the acetyl-cholinesterase (AchE) enzyme. Biochemical maturation of increasing specific activity of ChAT in both younger and older cells was taken into consideration.

The mathematical analysis of spontaneous and induced potentials in neural cultures.

We compare the power spectra of activities of neural cultures from the cortex and spinal cord of embryonic rat. The measurements were made in a microelectrode culture chamber by non-invasive methods. The data suggest that the fundamental frequencies of cortical and spinal cultures significantly differ, while the general patterns of the spectra are rather similar.

Multielectrode culture chamber: a device for long-term recording of bioelectric activities in vitro.

A multi-microelectrode culture chamber system was constructed for monitoring simultaneously morphological and electrophysiological development of neural cells in vitro. The setup consisted of a pattern of gold conductor lines evaporated onto a glass substrate and insulated with polyamide. The width of each electrode was 10 microns, and the distance between the electrodes was 60 microns.

Colloidal gold-labeled lipoprotein binding and internalization in adrenocortical cells in vitro.

Human (normal and adenomatous) and rat (normal) adrenocortical cells were incubated in vitro with colloidal gold labeled low-density (LDL-Au) and high-density (HDL-Au) lipoproteins, respectively, in order to visualize lipoprotein binding and internalization at an electron microscopic level. Both normal and adenomatous human adrenocortical cells accumulated LDL-Au by receptor-mediated endocytosis via coated pits, coated vesicles, noncoated vesicles, and lysosomes. HDL-Au was not internalized.

45Ca2+ uptake and peptide hormones secretion in the presence of excess Mg2+ content.

Studies have been performed on the relationship between PRL and GH production and the 45Ca2+ influx in high magnesium content in vitro. The obtained data show that an elevated magnesium concentration in Krebs-Ringer solution is capable of inhibiting some hormonal function of the pituitary gland. It has been found, that PRL and GH released into the media in normal KRB solution revealed nearly two times higher concentration than in the presence of high Mg2+.

Molecular form of human lymphocyte membrane-bound acetylcholinesterase.

The membrane-bound acetylcholinesterase (AchE) from human peripheral blood lymphocyte gives only one symmetrical peak on sucrose density gradient centrifugation in the presence of Triton X-100 detergent, with the calculated sedimentation coefficient of 6.5 S. However, this dimeric form of AchE was converted to a monomeric 3.

Proteinase inhibitors while influencing hormone release do not affect cell morphology of hypophyseal cultures.

Cultured cells from adult rat anterior pituitaries and intermediate lobes were treated with proteinase inhibitor substrate analogues (Boc-DPhe-Pro-Arginal [BOC-DPPA], DPhe-Pro-Arginal [DPPA], BOC-DPhe-Leu-Lysinal [BOC-DPLL], BOC-DPhe-Phe-Lysinal [BOC-DPPL]) to elucidate their effect on cell morphology. It was established that BOC-DPPA and DPPA (which in previous studies stimulated alpha-MSH release [6]) caused a slight decrease in the number of immunoreactive secretory granules in melanotrophs. BOC-DPLL, which inhibited growth hormone and prolactin release, did not alter the fine structural features of cultured cells.

Dissimilar responsiveness of cultured corticotrophs and melanotrophs to tripeptide aldehydes.

Cultured cells from adult rat anterior pituitaries or intermediate lobes were treated with the proteinase inhibitor tripeptide aldehydes BOC-DPhe-Pro-Arg-H (Boc-fPRH) and DPhe-Pro-Arg-H (fPRH), ovine corticotropin-releasing factor (oCRF), and bromocriptine. One millimolar fPRH stimulated basal, and slightly enhanced oCRF-induced ACTH release by melanotrophs in short-term experiments. The basal release of alpha-MSH was also stimulated by the drug.

Long-term suspension culture of isolated hypothalamic nuclei of the rat: morphological differentiation and release of substances influencing corticotropin and growth hormone secretion.

Individual hypothalamic nuclei were removed from 17-day-old rat embryos with 300 microns punches and maintained in suspension culture. Suspension culture of isolated nuclei appears to be suitable for studying morphological and functional differentiation of neural tissue and release of bioactivity influencing corticotropin and growth hormone release. During the 4 weeks in culture, neurons and glial cells differentiated well in each nucleus studied.

Lung maturation and prevention of hyaline membrane disease.

Small pieces of 7 to 12 week old human foetal lung, derived from legal abortions, were maintained in organ culture for 21 days. In the last 5 days of cultivation the explants were treated with dexamethasone (10 ng/ml) or betamethasone (10 ng/ml) or fenoterol (10 ng/ml), or fenoterol + dexamethasone, or bromhexine VIII metabolite (ambroxol: 12 ng/ml) and were then prepared for electronmicroscopic examination. In another experimental group the pregnant were treated before the interruption of 14-17-week old pregnancies with ambroxol (total dose, 1080 mg).

Responsiveness of intermediate lobe cells to neural mediators in culture.

Immunologically and biologically active ACTH, as well as biologically active alpha-MSH were secreted by monolayer cultures of rat pituitary intermediate lobe cells. The release of the immunoreactive ACTH and the bioactive alpha-MSH was inhibited by dopamine and by the dopamine agonist bromocriptine. The inhibition is probably mediated by specific dopaminergic receptors, since simultaneously added haloperidol prevented the dopamine induced hormone release inhibition.

GnRH secreting cultured fetal rat hypothalamic cells do not degrade GnRH.

The possible degradation of GnRH in the hypothalamus was investigated. Rat fetal hypothalamic cells were kept in culture for two weeks and basal and stimulated GnRH release was measured by highly sensitive RIA. These intact hypothalamic cells did not degrade GnRH during 4 hours of incubation, but a 50% degradation occurred after 24 hours incubation followed by HPLC using specifically tritium labeled GnRH or RIA.

[Effect of beta adrenergic drugs on phospholipid synthesis in the human fetal lung].

Human fetal lungs originating from legal absortion (n:16) (8-12 weeks) were cultured for 3 weeks. The effects of beta-adrenergic and/or corticosteroid stimulation on the synthesis of osmiophilic lamellar bodies i.e.

Induction of lamellar body synthesis by corticosteroids in first-trimester human fetal lungs.

Small pieces of 7- to 12-week-old human fetal lung, originating from legal abortions, were maintained in organ culture for 21 days. In the last 5 days of cultivation the explants were treated with dexamethasone (10 ng/ml) or betamethasone (10 ng/ml) and were then prepared for electron-microscopic examination. In response to corticosteroid treatment numerous characteristic osmiophilic lamellar bodies had developed in the cytoplasm of alveolar cells.

[Induction of osmiophilic lamellar bodies by corticosteroids, Fenoterol and Ambroxol in lung tissue cultures from human fetuses].

Organ cultures were set up from human fetal lung originating from the first trimester of gestation (8-12 weeks) and followed their morphological differentiation in the absence and in the presence of Dexamethasone, Betamethasone, Ambroxol and Dexamethasone + Fenoterol. We were especially interested in studying whether multilamellar bodies and tubular myelin structures which are characteristic of the human surfactant, could be demonstrated in the cells after different treatment. Dexamethasone and Betamethasone promoted directly the development of the multilamellar bodies and the tubular myelin structures in the type II cells.

Functional and morphological characteristics of isolated pancreatic islets in tissue culture.

Islets were isolated from the pancreas of female rats by using the collagenase technique. After culturing for 4 days, the islets were taken for measurement of insulin release biosynthesis as well as glucose utilization in subsequent short-time incubations. A low glucose concentration was insufficient to maintain a glucose-stimulated insulin release in vitro.