Effects of adrenergic and cholinergic agonists on adenylate and guanylate cyclase activity of isolated guinea-pig seminal vesicle epithelium.

Isolated seminal vesicle epithelium of the guinea-pig contained increased amounts of cAMP and cGMP after treatment with PGE1 and carbachol, respectively. Adrenergic agents had no influence. Possible physiological implications of these results are discussed.     

Peripherally located adrenergic neurons innervating the vas deferens and the seminal vesicle of the guinea-pig

Zusammenfassung Samenleiter und Samenblase vom Meerschweinchen besitzen eine besonders kräftige adrenergische Innervierung, die von Nervenzellen, die in unmittelbarer Nähe der Organe liegen, ausgeht.

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This work has been supported by grants from the United States Public Health Service (NB 02854-04) and from Stiftelsen Magnus Bergvalls Minne.     

Divergent effects of theophylline on adenylate cyclase preparations from guinea-pig heart and lung

Zusammenfassung Theophyllin verringert die Aktivität der Adenyl-Cyclase (AC) in der plasmamembranreichen Fraktion der Meerschweinchenlunge in Konzentrationen von 6–10 mM; es hat dagegen keinen Einfluss auf die Aktivität der AC in Meerschweinchenherzen. Diese Resultate weisen darauf hin, dass in verschiedenen Geweben geringe Unterschiede in der Enzym-Katalyse bestehen können.     

Effect of theophylline on myocardial adenylate cyclase activity

Summary Theophylline (0.01–10.0 mM) did not incease but rather decreased adenylate cyclase activity (AC) of guineapig auricles. Isoprenaline (1–100 M) and sodium fluoride (0.3–10.0 mM)stimulated AC in aconcentration-dependent manner.This work was supported by the Deutsche Forschungsgemeinschaft. The continous advice of Dr U. Schwabe is gratefully acknowledged.     

Beta-adrenergic-stimulated adenylate cyclase activity in normal and EBV-transformed lymphocytes

Summary Beta-adrenergic-associated cyclic AMP accumulation was studied in intact lymphocytes before and after transformation with Epstein-Barr virus into immortal cell lines. Although a marked reduction in isoproterenol-stimulated cyclic AMP synthesis was observed in transformed cells, forskolin-stimulated cyclic AMP accumulation was preserved. A parallel loss of¹²⁵-iodocyanopindolol binding sites suggests that the reduction in beta-adrenergic-stimulated AMP synthesis is due to receptor down regulation.     

Beta-adrenergic-stimulated adenylate cyclase activity in normal and EBV-transformed lymphocytes

Beta-adrenergic-associated cyclic AMP accumulation was studied in intact lymphocytes before and after transformation with Epstein-Barr virus into immortal cell lines. Although a marked reduction in isoproterenol-stimulated cyclic AMP synthesis was observed in transformed cells, forskolin-stimulated cyclic AMP accumulation was preserved. A parallel loss of 125-iodocyanopindolol binding sites suggests that the reduction in beta-adrenergic-stimulated AMP synthesis is due to receptor down-regulation.     

Postnatal development of adrenergic and cholinergic sensitivity in the isolated rat atria

Summary The sensitivity to adrenergic drugs in isolated rat atria increased with the postnatal development. The cholinergic chronotropic sensitivity did not further change after birth.     

Postnatal development of adrenergic and cholinergic sensitivity in the isolated rat atria

The sensitivity to adrenergic drugs in isolated rat atria increased with the postnatal development. The cholinergic chronotropic sensitivity did not further change after birth.     

Effect of castration and testosterone administration on the noradrenaline content of the vas deferens and the seminal vesicle of the guinea-pig

Zusammenfassung Die Noradrenalinkonzentration im Vas deferens und den Vesiculae seminales erhöht sich nach Kastration, wird aber nach Behandlung mit Testosteron leicht vermindert. Der gesamte Noradrenalingehalt erfährt jedoch nach keiner der beiden Behandlungen eine bedeutende Veränderung verglichen mit unbehandelten Kontrollorganen. Das bedeutet, dass Androgene keinen ausgesprochenen Einfluss auf die adrenergische Innervation per se haben, sondern hauptsächlich Gewebe, wie Glattmuskel- und sekretorische Zellen, influieren.     

Effects of penfluridol on dopamine-sensitive adenylate cyclase in corpus striatum and substantia nigra of rats

Summary Penfluridol, a neuroleptic with diphenylbutyl piperidine structure, blocked the dopamine-sensitive adenylate cyclase in homogenates of corpus striatum and substantia nigra of rats, probably by a competitive antagonism versus dopamine.Acknowledgment. We thank Dr P. Janssen (Beerse, Belgium) for a generous gift of penfluridol.     

Effects of the adenylate cyclase activator forskolin and its inactive derivative 1,9-dideoxyforskolin on insect cytochrome P-450 dependent steroid hydroxylase activity

The adenylate cyclase activator forskolin and its pharmacologically inactive derivative 1,9-dideoxyforskolin were found to inhibit in a dose-dependent fashion the ecdysone 20-monooxygenase activity associated with wandering stage larvae ofDrosophila melanogaster and fat body and midgut from last instar larvae of the tobacco hornworm,Manduca sexta. The concentrations of these labdane diterpenes required to elicit a 50% inhibition of the cytochrome P-450 dependent steroid hydroxylase activity in the insect tissues ranged from approximately 5×10^–6 to 5×10^–4 M.     

Effects of the adenylate cyclase activator forskolin and its inactive derivative 1,9-dideoxyforskolin on insect cytochrome P-450 dependent steroid hydroxylase activity.

The adenylate cyclase activator forskolin and its pharmacologically inactive derivative 1,9-dideoxyforskolin were found to inhibit in a dose-dependent fashion the ecdysone 20-monooxygenase activity associated with wandering stage larvae of Drosophila melanogaster and fat body and midgut from last instar larvae of the tobacco hornworm, Manduca sexta. The concentrations of these labdane diterpenes required to elicit a 50% inhibition of the cytochrome P-450 dependent steroid hydroxylase activity in the insect tissues ranged from approximately 5 x 10(-6) to 5 x 10(-4) M.     

Effects of penfluridol of dopamine-sensitive adenylate cyclase in corpus striatum and substantia nigra of rats.

Penfluridol, a neuroleptic with diphenylbutyl piperidine structure, blocked the dopamine-sensitive adenylate cyclase in homogenates of corpus striatum and substantia nigra of rats, probably by a competitive antagonism versus dopamine.     

Endotoxin inhibits the fluoride-stimulated adenylate cyclase activity of rat liver plasma membranes enriched with bile canaliculi

Summary Escherichia coli endotoxin inhibited the fluoride-stimulated adenylate cyclase activity of liver plasma membranes enriched with bile canaliculi. Inhibition was of a mixed competitive and uncompetitive type. This effect, which may result from changes of membrane organization, may have relevance in the understanding of endotoxin-cell membrane interactions.     

The relation between cell proliferation and adenylate cyclase activity in grafts of 3-methylcholanthrene induced mouse uterine cervical tumors

Summary In transplanted uterine cervical tumors, induced by 3-methylcholanthrene, a significant negative correlation was obtained between adenylate cyclase activity and cell proliferation.     

The effect of proctolin on the adenylate and guanylate cyclases in theLocusta brain at various developmental stages

Summary Proctolin at concentrations 10^–8–10^–7 M elevated by 40% brain adenylate cyclase activity of adultLocusta migratoria migratorioides R.F. In moulting individuals, proctolin caused a decrease in brain adenylate cyclase activity, and it proved to be ineffective in the larvae. Proctolin caused only a slight decrease on guanylate cyclase activity of the brain at every developmental stage.     

Effect of high doses of somatostatin on adenylate cyclase activity in peripheral mononuclear leukocytes from normal subjects and from acute leukemia patients

Summary In normal lymphocytes somatostatin non-competitively inhibited basal (ID₅₀ 5×10^–4 M) and isoproterenol- and forskolin-stimulated adenylate cyclase activity (Ac). In acute leukemia blasts, non-responsive to isoproterenol, forskolin, which activates the catalytic subunit, stimulated and somatostatin inhibited Ac, thus indicating the leukemic enzyme, though defective, retains the inhibitory pathway and catalyst function.     

Electrically-induced mechanical activity of the isolated guinea-pig sciatic nerve. Influences of calcium and anoxia

Summary The electrically induced motility of isolated segments of guinea-pig sciatic nerves is reported. This motility was characterized by waves of tensional variations. The removal of Ca²⁺ from the suspending solution, the addition of EDTA as well as anoxia, resulted in a decrement of tension accompanied by a prolongued duration of the cycles of mechanical activity.This work was supported by grant 6638, from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina (C.O.N.I.C.E.T.).