Maprotiline treatment differentially influences cardiac β -adrenoreceptors expression under normal and stress conditions

Alterations in cardiac function were observed in antidepressants treated patients and published in several clinical reports. These detected changes could be either a consequence of the treatment or of depression itself, which has already been proved to be a risk factor in heart diseases. In order to determine a possible influence of chronic treatment with norepinephrinergic reuptake inhibitor, maprotiline, on the heart, we investigated gene expression of cardiac β-adrenoceptors both in controls and in animals with signs of depression. The rats were divided into two groups, unstressed controls and those exposed to chronic unpredictable mild stress (CUMS). The groups were further divided into two subgroups, one receiving daily intraperitoneal injections of vehicle (sterile water) and another one maprotiline (10 mg/kg) for four weeks. Tissue samples were collected after the last application. Gene expression of cardiac β1- and β2-adrenoceptor was determined using Real-time RT-PCR analysis. Our results show that in control animals expression of both adrenoreceptors was decreased in the right atria after 4 weeks of maprotiline application. Contrary, the same treatment led to a significant increase in expression of cardiac β1-adrenoceptor in the stressed rats, with no change in the characteristics of β2-adrenoceptor. Our findings might reflect the that molecular mechanisms are underlying factors involved in the development of cardiovascular diseases linked with antidepressant treatment.

Vários relatórios clínicos observaram alterações de funcionamento cardíaco de pacientes depressivos que foram tratados com os antidepressivos. As alterações detectadas podem ser consequência do tratamento ou, por outro lado, da depressão que, como se tem provado, é um fator de risco no caso de doenças cardíacas. De modo a determinar a possível influência de tratamento crônico com o inibidor da recaptação de norepinefrina, maprotilina, no coração, foi investigada a expressão do gene aos receptores β-adrenérgicos cardíacos dos animais em grupos de controle e em grupos com sinais de depressão. Os ratos foram divididos em grupos de controle não estressados e os grupos de ratos submetidos ao estresse crônico moderado imprevisível (CUMS). Os grupos foram, ainda, divididos em dois subgrupos, que, durante quatro semanas, diariamente receberam injeções intraperitoneais de placebo (água estéril) ou de maprotilina (10 mg/kg). As amostras de tecido foram coletadas após a última aplicação. A expressão do gene aos receptores adrenérgicos β1 e β2 foi determinada utilizando a análise PCR quantitativa em tempo real (RT-PCR). Os nossos resultados demonstram a diminuição de expressão dos ambos os receptores adrenérgicos no átrio direito dos animais do grupo de controle depois de quatro semanas de aplicação de maprotilina. Em contraste, o mesmo tratamento conduziu ao aumento significativo na expressão do receptor β1-adrenérgico no coração dos ratos estressados, sem qualquer alteração nas características do receptor β2-adrenérgico. Estes resultados podem refletir os mecanismos moleculares envolvidos no desenvolvimento de doenças cardiovasculares associadas ao tratamento com os antidepressivos.

[From lab to clinical activity: adrenergic receptors and human uro-genital tissues]. / Dal laboratorio alla clinica: recettori adrenergici e tessuti umani dell'apparato uro-genitale.

BACKGROUND: Nowadays translational medicine is acquiring a more and more important role in connecting laboratory experimental results on human tissues to clinical findings and drug employment. We want to underline the importance of in vitro studies, which have been extensively performed on animal organs, but few studies have been performed on human tissues. Nevertheless, a more accurate result when compared to the in vivo use of drugs can be given only by testing the very same human tissues in a lab. We related clinical treatments of different pathologies with the results obtained in laboratory studying in vitro fragments of human organs extracted during surgery exposed to different mediators and drugs. METHODS: Fragments of urethers, bladder (detrusorial muscle and bladder neck muscle fibers), corpora cavernosa, and vas deferens were extracted during demolitive surgery trying not to traumatize the tissue, in order to keep it alive and not to ruin its contractile fibers. The fragments were then put into polisaline solution and, once in the laboratory, fixed on suitable isolated organ support, fixed at one side of the thermostatic pool and on the other side connected to a digital monitoring system. The contractility was then studied after adding different mediators. RESULTS: The urethers have shown a stronger response to NE and PGF2a, with a different contractility in their distal part due to a major concentration of alpha-receptors; the bladder neck has also shown a strong contractile response to NE and PGF2a, and is inhibited by alpha-blockers; the bladder detrusor, instead, responds to ACH (acetylcholine) and PGF2a; the vas deferens shows a different type of contractility in the prostatic part compared to the epididimary part when stimulated with noradrenaline and PGF2a; the corpora cavernosa respond to NE and PGF2a. CONCLUSIONS: The results obtained after stimulating the fragments can explain and prove the receptorial activity of inner mediators and of commonly used drugs which have, for years, been used empirically; the simplicity and repetitivity of the method can be considered and used not only to research the physiological functioning of different organs, but also the functioning of new drugs before testing them on patients, being more reliable and accurate than tests on animal tissues. This experimental work has shown that using human tissues in testing specific mediators is the most reliable laboratory method.

Lymphocytic infiltration and goblet cell marker alteration in the conjunctiva of the MRL/MpJ-Fas(lpr) mouse model of Sjögren's syndrome.

Sjögren's syndrome is an autoimmune disorder characterized by a progressive, immune-mediated destruction of mucosal tissues such as the lacrimal and salivary glands, leading to ocular and oral dryness. The MRL/MpJ-Fas(lpr) mouse is one of the animal models used to study this disease. However, little is known about the potential alterations in the conjunctiva in this murine model. The purpose of this study was to determine: (1) whether the conjunctiva is infiltrated by T lymphocytes, (2) characterize the type, amount and temporal sequence of the inflammatory infiltrates, and (3) investigate whether the amount of conjunctival goblet cells is altered in this murine model of Sjögren's syndrome. Female 4-, 9-, 13-, 16-, and 18-/20-wk-old MRL/MpJ-Fas(lpr) (lpr, diseased) and congenic MRL/MpJ (+/+, control) mice were used. Right eyes were either fixed, frozen, cryosectioned, and studied by immunofluorescence microscopy or the conjunctiva was removed, homogenized and analyzed by electrophoresis and Western blot analysis. The following antibodies were used: anti-CD3 (specific T lymphocyte marker), anti-cytokeratin 7 (CK-7), anti-PKD (formerly known as PKCmu, both markers of goblet cell bodies), anti-PGP 9.5 (pan-neuronal marker), anti-VIP and TH (markers for parasympathetic and sympathetic nerves, respectively), anti-adrenergic (alpha(1) and beta(1-3)) and muscarinic (M(1)-M(3)) receptor subtypes (markers for neurotransmitter receptors of the sympathetic and parasympathetic pathways, respectively). Left eyes were fixed, embedded, sectioned, and stained. Hematoxylin/eosin, Giemsa, or alcian blue/periodic acid Schiff's reagent were used to study lymphocyte infiltration; to determine the presence of eosinophils, neutrophils, and mast cells; and to count the number of goblet cells, respectively. By immunofluorescence microscopy, lymphocytes were detected in the conjunctiva of 9-wk-old lpr, but not +/+, mice. The lymphocytic infiltration became more extensive as the animals aged, with 16- and 18-/20-wk lpr mice appearing to have a greater lymphocytic infiltration than +/+ mice at the same age. By Western blot analysis, the amount of CD3 was enhanced in lpr compared to +/+ mice by the 16th wk, but not by the 9th wk. No major differences in the presence of eosinophils, neutrophils and degranulated mast cells between lpr and +/+ mice were observed. By light microscopy, a significant increase in goblet cell number was found in lpr mice compared to +/+ mice at 16 wks on. By Western blotting, the amount of CK-7 was significantly increased at 9 wks on and the amount of PKD was significantly increased at 16 wks. By immunofluorescence microscopy, there were no major differences in distribution of sympathetic and parasympathetic nerves present in the lpr conjunctiva compared to that of +/+ mice at any ages, although slight differences were observed with increased age. Muscarinic receptor expression was decreased, as less M(3) receptor subtype-associated immunofluorescence was detected in older lpr mice compared to +/+ mice and confirmed by Western blot analysis. No differences in the localization or the amount of alpha(1)- or beta(1-3)-adrenergic receptor immunodetection were observed between lpr and +/+ mice. We conclude that the conjunctiva is a target tissue in Sjögren's syndrome-related inflammation in this murine model.

Epithelial distribution of neural receptors in the guinea pig small intestine.

Neural and paracrine agents, such as dopamine, epinephrine, and histamine, affect intestinal epithelial function, but it is unclear if these agents act on receptors directly at the enterocyte level. The cellular localization and villus-crypt distribution of adrenergic, dopamine, and histamine receptors within the intestinal epithelium is obscure and needs to be identified. Single cell populations of villus or crypt epithelial cells were isolated from the jejunum of adult guinea pigs. Enterocytes were separated from intraepithelial lymphocytes by flow cytometry and specific binding was determined using fluorescent probes. Alpha1-adrenergic receptors were located on villus and crypt intraepithelial lymphocytes and enterocytes. Beta-adrenergic receptors were found on villus and crypt enterocytes. Dopamine receptors were found on all cell types examined, whereas histamine receptors were not detected (<10% for each cell population). These studies demonstrated that (1) receptors for epinephrine and dopamine exist on epithelial cells of the guinea pig jejunum, (2) beta-adrenergic receptors are found primarily on villus and crypt enterocytes and (3) intraepithelial lymphocytes contain alpha1-adrenergic, but have few beta-adrenergic, receptors. The presence of neural receptors suggests that these agents are acting, at least in part, at the enterocyte or intraepithelial lymphocyte levels to modulate intestinal and immune function.

Immunomodulation by the autonomic nervous system: therapeutic approach for cancer, collagen diseases, and inflammatory bowel diseases.

The distribution of leukocytes is regulated by the autonomic nervous system in humans and animals. The number and function of granulocytes are stimulated by sympathetic nerves whereas those of lymphocytes are stimulated by parasympathetic nerves. This is because granulocytes bear adrenergic receptors, but lymphocytes bear cholinergic receptors on the surface. These regulations may be beneficial to protect the body of living beings. However, when the autonomic nervous system deviates too much to one direction, we fall victim to certain diseases. For example, severe physical or mental stress --> sympathetic nerve activation --> granulocytosis --> tissue damage, including collagen diseases, inflammatory bowel diseases, and cancer. If we introduce the concept of immunomodulation by the autonomic nervous system, a new approach for collagen diseases, inflammatory bowel diseases, and even cancer is raised. With this approach, we believe that these diseases are no longer incurable.

Benign prostatic hyperplasia: correlations between receptor density and binding affinity of alpha(1)-adrenoceptors and several clinical parameters.

The aim of the study was to determine whether relations do exist between the concentration and activity of alpha(1)-adrenoceptors, both inside the prostatic adenoma and the periurethral zone corresponding to the bladder neck, and clinical and biological parameters such as symptoms, evaluated by the American Urological Association (AUA) score, age, weight of the prostate, PSA, and the flow rate. Twenty patients with symptomatic benign prostatic hyperplasia were selected for an open prostatectomy. One gram of tissue was dissected from inside the adenoma and 1 g from the periurethral zone corresponding to the bladder neck. The alpha(1)-adrenoceptors were evaluated for the apparent dissociation constant (K(d)) and the maximal number of binding sites (B(max)). A correlation seems to exist between receptor density inside the adenoma and the bladder neck and an inverse correlation between receptor density and the AUA total symptoms score. Finally, a highly significant difference was found in patients with an AUA score of <15 or >15. No relationship was found between receptor binding affinity and the considered clinical parameters.

Norepinephrine content and adrenoceptor function in the bladder of cats with feline interstitial cystitis.

PURPOSE: Interstitial cystitis is a chronic syndrome affecting humans and domestic animals, including cats (feline interstitial cystitis). The aggravation of interstitial cystitis symptoms by stress suggests involvement of the sympathetic nervous system. Studies have identified increased sympathetic nervous system activity in patients with interstitial cystitis but to our knowledge effects on bladder function have not been reported. To address this question we measured bladder norepinephrine (NE) content, the electrical field stimulation flux of NE and acetylcholine (ACh), and the effects of feline interstitial cystitis on adrenoceptor (AR) mediated bladder strip contractility. MATERIALS AND METHODS: Bladders were obtained from healthy cats and cats with feline interstitial cystitis. In experiment 1 bladder tissue NE content was determined and the simultaneous release of 3H-NE and 14C-ACh in perfusion bath effluent after electrical field stimulation was measured. NE and ACh release was calculated from the area under the efflux curve. In experiment 2 electrical field stimulation induced contractility of bladder body strips was measured in the presence of 100 nM. to 25 microM. NE only or combined with atipamezole (an alpha2-AR antagonist), propranolol (a beta-AR antagonist) or phentolamine (an alpha-AR antagonist). Antagonists were added to the bath at least 15 minutes before stimulation, after which NE was added in cumulative doses and dose response curves were constructed. RESULTS: Significant increases in NE content and efflux in the absence of alterations in ACh efflux were identified. In the bladder strip studies decreased alpha2 and beta1-AR function was found in strips from cats with feline interstitial cystitis, whereas beta3 or atypical beta-ARs were tentatively identified. CONCLUSIONS: These results support and extend previous studies by identifying an effect of increased sympathetic activity on bladder function in cats with feline interstitial cystitis.

The sympathetic nerve--an integrative interface between two supersystems: the brain and the immune system.

The brain and the immune system are the two major adaptive systems of the body. During an immune response the brain and the immune system "talk to each other" and this process is essential for maintaining homeostasis. Two major pathway systems are involved in this cross-talk: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). This overview focuses on the role of SNS in neuroimmune interactions, an area that has received much less attention than the role of HPA axis. Evidence accumulated over the last 20 years suggests that norepinephrine (NE) fulfills the criteria for neurotransmitter/neuromodulator in lymphoid organs. Thus, primary and secondary lymphoid organs receive extensive sympathetic/noradrenergic innervation. Under stimulation, NE is released from the sympathetic nerve terminals in these organs, and the target immune cells express adrenoreceptors. Through stimulation of these receptors, locally released NE, or circulating catecholamines such as epinephrine, affect lymphocyte traffic, circulation, and proliferation, and modulate cytokine production and the functional activity of different lymphoid cells. Although there exists substantial sympathetic innervation in the bone marrow, and particularly in the thymus and mucosal tissues, our knowledge about the effect of the sympathetic neural input on hematopoiesis, thymocyte development, and mucosal immunity is extremely modest. In addition, recent evidence is discussed that NE and epinephrine, through stimulation of the beta(2)-adrenoreceptor-cAMP-protein kinase A pathway, inhibit the production of type 1/proinflammatory cytokines, such as interleukin (IL-12), tumor necrosis factor-alpha, and interferon-gamma by antigen-presenting cells and T helper (Th) 1 cells, whereas they stimulate the production of type 2/anti-inflammatory cytokines such as IL-10 and transforming growth factor-beta. Through this mechanism, systemically, endogenous catecholamines may cause a selective suppression of Th1 responses and cellular immunity, and a Th2 shift toward dominance of humoral immunity. On the other hand, in certain local responses, and under certain conditions, catecholamines may actually boost regional immune responses, through induction of IL-1, tumor necrosis factor-alpha, and primarily IL-8 production. Thus, the activation of SNS during an immune response might be aimed to localize the inflammatory response, through induction of neutrophil accumulation and stimulation of more specific humoral immune responses, although systemically it may suppress Th1 responses, and, thus protect the organism from the detrimental effects of proinflammatory cytokines and other products of activated macrophages. The above-mentioned immunomodulatory effects of catecholamines and the role of SNS are also discussed in the context of their clinical implication in certain infections, major injury and sepsis, autoimmunity, chronic pain and fatigue syndromes, and tumor growth. Finally, the pharmacological manipulation of the sympathetic-immune interface is reviewed with focus on new therapeutic strategies using selective alpha(2)- and beta(2)-adrenoreceptor agonists and antagonists and inhibitors of phosphodiesterase type IV in the treatment of experimental models of autoimmune diseases, fibromyalgia, and chronic fatigue syndrome.

Glutaminergic and adrenergic receptors expressed on adult guinea pig Schwann cells in vitro.

We have investigated the responsiveness of adult guinea pig Schwann cells to a range of neuroligands, using ratiometric calcium imaging. The majority of cells responded to ATP (90 +/- 4%), adrenaline (57 +/- 5%), and noradrenaline (61 +/- 5%), as well as glutamate (60 +/- 5%). The number of cells responding to glutamate increased significantly (90 +/- 4%; p < 0.01) when the cells were grown in excitatory amino acid (EAA) free medium, indicating EAA-induced downregulation. Only a small number of cells (9 +/- 2%) responded to acetylcholine. Agonist and antagonist experiments show that these adult Schwann cells predominantly express ionotropic glutaminergic receptors (N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isooxazolepropionic acid (AMPA), and kainate) as well as alpha1-, alpha2-, and beta-adrenoreceptors. We conclude that Schwann cells derived from adult guinea pigs express a variety of neuroligand receptors when established in culture and are particularly rich in glutamate receptors. This probably reflects a de-differentiated state important to development and regeneration.

Alterations in cardiac membrane beta-adrenoceptors and adenylyl cyclase due to hypochlorous acid.

Although neutrophils and eosinophils are known to produce hypochlorous acid (HOCI) at the site of cardiac injury, the exact role of this toxic oxidant on the signal transduction mechanism in the heart is not clear. In this study, the effects of HOCI on beta-adrenoceptors, G-proteins and adenylyl cyclase activity were assessed by incubating rat heart membranes with HOCl. The basal as well as forskolin-, NaF-, 5-guanylylimidodiphosphate-, and isoproterenol-stimulated adenylyl cyclase activities were depressed by incubating cardiac membranes with HOCl. While both the density and affinity of the beta1-adrenoceptors were decreased by treatment of cardiac membranes with HOCl, the characteristics of the beta2-adrenoceptors were not modified significantly. Although cholera toxin-stimulated adenylyl cyclase activity, cholera toxin-catalyzed ADP-ribosylation and stimulatory guanine nucleotide binding protein immunoreactivity were depressed by HOCl, the pertussis toxin-stimulated adenylyl cyclase activity, pertussis toxin-catalyzed ADP ribosylation and inhibitory guanine nucleotide binding protein immunoreactivity were unaltered by HOCl. The presence of L-methionine in the incubation medium prevented the HOCl-induced alterations in adenylyl cyclase activities and characteristics of beta1-adrenoceptors. These results suggest that HOCl may be one of the factors attenuating the beta-adrenoceptor linked signal transduction mechanism in conditions such as ischemic heart disease.

Non-adrenergic, non-cholinergic neurons innervating the guinea-pig trachea are located in the oesophagus: evidence from retrograde neuronal tracing.

The possibility that non-adrenergic, non-cholinergic (NANC) neurons innervating the guinea-pig trachea may be located within the oesophagus has been investigated using an in vitro retrograde tracing technique. The cervical trachea and oesophagus were excised from guinea-pigs and Dil was applied to a 5 mm region of the trachealis muscle. These preparations were maintained in organotypic culture for 3 days and processed for immunohistochemistry. A mean of 44 (4 neural cell bodies in the oesophageal myenteric plexus were found to be labelled by Dil. The vast majority of these neurons contained nitric oxide synthase, vasoactive intestinal polypeptide and neuropeptide Y. It is suggested that the population of neurons identified in this study are postganglionic parasympathetic neurons mediating NANC relaxation of the trachealis muscle in this species.

Viable AC-2, a new adult bovine serum- and colostrum-based supplement for the culture of mammalian cells.

In this study we have shown that Viable AC-2, a medium based on the ultrafiltrate fraction of bovine colostrum and adult bovine serum, can be used successfully as a fetal bovine serum (FBS) substitute in the culture of several anchorage-dependent and independent cell lines. Of the 15 cell lines cultured in 8% Viable AC-2 in microplates, 10 reached the maximum cell density of 65%-123% of that in 10% FBS, 4 cell lines reached maximum cell density of 35%-65% of that in 10% FBS and only one cell line, a human osteosarcoma G-292, grew slowly in Viable AC-2. In a small-scale suspension culture, 8%-15% Viable AC-2 supports the growth of Chinese hamster ovary cells (CHO-K1) on microcarriers in spinner flasks significantly better than 10% FBS. Shionogi mouse mammary tumour cell line (S115) transfected with human alpha 2-adrenergic receptor subtype C2 was used as a model to study recombinant protein production in Viable AC-2-supplemented medium. The results showed that in cell culture flasks and in an ACUSYST-R bioreactor, the alpha 2-C2 receptor expression level per mg of total protein was similar in both Viable AC-2 and FBS.

Distribution and density of monoamine receptors in the primate visual cortex devoid of retinal input from early embryonic stages.

Developmental mechanisms that regulate the areal and laminar distribution of various macromolecules, including neurotransmitter receptors in the cerebral cortex, are not known. In the present study, we examined the development of monoaminergic receptors in the rhesus monkey striate and peristriate visual cortex in the absence of input from the retina. Binocular enucleation was performed between embryonic days E60 and E81, prior to the ingrowth of geniculocortical fibers into the cortical plate and before genesis of the granular and supragranular layers of the visual cortex. The animals were delivered at term (E165) and sacrificed at 2 or 12 months of age, and their brains frozen and the occipital lobes cut at 20 microns in the coronal plane. Cortical binding of 3H-clonidine, 125I-pindolol, 3H-5-HT, 3H-ketanserin, 3H-spiperone, 3H-SCH23390, and 3H-prazosin that label various monoamine receptors were autoradiographically visualized and quantified using a computer imaging system. All radioligands displayed specific laminar patterns in the striate and prestriate areas in both groups of animals. The areal and laminar distribution in the anophthalmic monkeys was similar to that in the controls. Significantly, in all enucleated animals, just as in the controls, a particularly high density of 3H-clonidine and 3H-prazosin was observed in the sublayers of layer IV involved in color vision. The present results show that the monoamine receptors in primate visual cortex can establish and maintain distinct laminar and areal patterns in the absence of activity or molecular cues originated from the retina, and provide new insight into the cortical consequences of secondary congenital anophthalmia.

Efectos de la clozapina sobre diferentes receptores / Clozapine effects on different receptors

Los experimentos se realizaron, con el propósito de valorar el efecto de la clozapina sobre los receptores a dopamina, norepinefrina, glutámico, GABA y acetilcolina. Se encontró, que los desplasamientos fueron principalmente y en orden de importancia, en los receptores M1/M2 de acetilcolina, y en los receptores a dopamina; los efectos encontrados en glutámico y GABA fueron principalmente en la corteza frontal y no se observo inhibición en la unión de norepinefrina por clozapina en ninguna área estudiada. Esto sugiere una participación importante de la corteza frontal, así como la presencia de estos receptores analizados, los cuales presentan una gran homología molecular, lo que habrá que estudiar desde diferentes puntos de vista

[Changes in human pulmonary receptors in tuberculosis, chronic pneumonia and cancer]. / Izmenenie retseptorov legkikh cheloveka pri tuberkuleze, khronicheskoi pnevmonii i rake.

The authors studied changes in beta- and alpha 1-adrenoceptors (beta-AC, alpha 1-AC) as well as in m-cholinoceptors in tuberculosis, pneumonia and cancer. Specimens of the lung parenchyma were obtained at thoracic surgery from 43 patients. Relevant ligands binding to the receptors was evaluated by incubation of the membrane proteins with radioligands varying in concentrations. Irrespective of the inflammation variant, beta-AC and alpha 1-AC levels were found decreased this being an correlation with the scope of fibrous and destructive involvement. The degree of the process chronicity and advance was judged from a decline in the binding parameters for beta-AC and alpha 1 AC. A dramatic fall in alpha 1 AC occurred in tuberculosis. This may be related to microcirculatory failure and vascular deformity. The levels of m-cholinoceptors underwent insignificant changes in pulmonary inflammation, whereas lung cancer displayed their sharp rise.

Studies on responsiveness of hepatoma cells to catecholamines. VI. Characteristics of adrenoceptors and adenylate cyclase response in rat ascites hepatoma cells and human hepatoma cells.

Alpha 1, alpha 2- and beta-Adrenoceptor densities and catecholamine responsiveness in established hepatoma cells, rat ascites hepatoma AH13, AH66, AH66F, AH109A, AH130 and AH7974 cells and human hepatocellular carcinoma HLF and HepG2 cells, were compared with those in normal rat hepatocytes and Chang liver cells. Alpha 1-Adrenoceptor densities measured by [3H]prazosin bindings were not detected in all hepatoma cell lines. Alpha 2-Adrenoceptor densities measured by [3H]clonidine bindings were also barely detected in hepatoma cell lines except for AH130 cells and HepG2 cells. Regarding beta-adrenoceptor, AH109A, AH130 and AH7974 cells had much more [125I]iodocyanopindolol binding sites than normal rat hepatocytes, although we could not detect the binding in HepG2 cells. Adenylate cyclase of normal rat hepatocyte and Chang liver cells were stimulated by beta 2-adrenergic agonist salbutamol, while the cyclase in hepatoma cells had no beta 2-adrenergic response but a beta 1-type response. These findings indicate that the characteristics of adrenergic response in hepatoma cell lines is very different from that in normal hepatocytes, suggesting a participation in the hepatocarcinogenesis and/or the autonomous proliferation of hepatoma cells.

The innervation of the closer muscle of the mesothoracic spiracle of the locust.

The closer muscle of the mesothoracic spiracle of the locust, Schistocerca gregaria is innervated by two excitatory motoneurones and also by processes of a peripherally located neurosecretory cell. Within the muscle, ultrastructural studies show the presence of two types of excitatory nerve terminal which differ in the content of dense cored vesicles and in their distribution. The ventral segment of the muscle is innervated predominantly by terminals with small clear vesicles and only an occasional dense-cored vesicle. The central part of the muscle is innervated predominantly by terminals with small clear vesicles and larger numbers of dense-cored vesicles. The dorsal segment of the muscle is innervated exclusively by a neurosecretory type innervation. The small neurohaemal organ of the median nerve close to the spiracle muscle is immunoreactive to an antibody raised against bovine pancreatic polypeptide but no immunoreactive processes enter the muscle itself. The muscle possesses specific octopaminergic receptors that increase cyclic AMP levels and the possibility that the neurosecretory input to the muscle is provided by either a central or peripheral octopamine containing neurone is discussed.

[Pregnancy-induced changes in adrenergic receptors]. / Schwangerschaftsbedingte Veränderungen adrenerger Rezeptoren.

In the 24th and 26th week of pregnancy and also 6 weeks post partum, n = 32 pregnant women were evaluated for the concentration of adrenergic receptors on blood cells by radioligand binding assay and an isoprenaline stimulation of the beta-receptors. The concentrations of estradiol and progesterone in serum were also determined and nephrosonography was carried out. The stimulation and concentration of the beta-receptors were significantly higher during pregnancy than post partum. The alpha-receptors displayed contrary alterations: Here, the concentration evaluated during pregnancy was considerably lower. No connection was determined between the progesterone level in serum and the extent of the receptor alterations. However, one was found with the estrogen level and the dilatation of the upper urinary tract: Pregnant women with pronounced alterations above the median showed a distinct decrease of estradiol and a marked dilatation of the kidney collecting system. Alterations in the adrenergic receptors can therefore be determined during pregnancy. The extent of the receptor fluctuation is connected to the estradiol concentration in serum and the dilatation of smooth muscle hollow organs.