Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to try to differentiate histochemically between the various enzymes which may catalyze the hydrolysis of ATP in developing rat dental tissues. Freeze cut and freeze dried sections of molar and incisor teeth were incubated in lead capture-based media at pH 5.0, 7.2 or 9.4 with one of the following substrates: beta-glycerophosphate, AMP, ADP, ATP, AMP-PNP and tetrasodium pyrophosphate. To establish the enzymatic nature of the hydrolysis parallel sections were incubated after prior fixation in either formaldehyde or glutaraldehyde. By comparing the enzymatic stainings obtained with the various substrates and at the different pH:s, it was concluded that ATP can be visibly hydrolyzed in rat dental tissues by alkaline phosphatase (stratum intermedium, apical part of maturation ameloblasts, basal part of all ameloblasts, odontoblasts and subodontoblastic layer), specific ATPase (apical and basal parts of secretory ameloblasts) and ATP pyrophosphatase and/or adenylate cyclase (stratum intermedium, odontoblasts). Acid phosphatase, specific ADPase, 5'-nucleotidase, inorganic pyrophosphatase, 3':5'-cyclic-AMP-phosphodiesterase and adenylate kinase on the other hand, seem not to be engaged in the ATP hydrolysis to such a degree as to complicate the interpretation of the histochemical staining. The alkaline phosphatase part of the ATP hydrolysis appeared to be rather insensitive to aldehyde fixation, while the hydrolysis effected by specific ATPase and ATP pyrophosphatase and/or adenylate cyclase was extinguished after fixation with formaldehyde for 4 h or glutaraldehyde for 10 min.
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PMID:Adenosine triphosphate hydrolysis in rat dental tissues. A histochemical study to differentiate the enzymes involved. 18 60

The LDL receptor synthesis of human skin fibroblasts in the presence of the specific calmodulin antagonists trifluoperazine, condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde (compound 48/80) and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide) (W-7) was studied. Labelling of cells with [35S]methionine followed by immunoprecipitation of radioactive LDL receptor protein with monospecific antibodies revealed that calmodulin antagonists caused a 3-fold increase in the radioactivity of the LDL receptor protein as compared with values found in control cells. A corresponding increase of high-affinity binding and internalization of 125I-labelled LDL was observed. The drugs did not influence the overall protein synthesis or the half-life of the LDL receptor. A concomitant suppression of cholesterol synthesis from [14C]mevalonolactone was found to be an independent effect. The calmodulin antagonist-produced stimulation of LDL receptor synthesis could not be simulated by preincubation of cells with cyclic nucleotide analogues, cholera toxin or 3-isobutyl-1-methylxanthine, known as specific effectors of adenylate cyclase and cyclic nucleotide phosphodiesterase, respectively. Modulation of calcium concentration in the incubation medium had no reproducible effect on the rate of LDL receptor synthesis. The results implicate calmodulin as an intracellular suppressor of LDL receptor synthesis in human skin fibroblasts.
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PMID:Calmodulin antagonists stimulate LDL receptor synthesis in human skin fibroblasts. 241 82

Cytosolic free calcium concentration [Ca2+] was studied in platelets of hypertensive patients with the use of the fluorescent indicator Quin 2/AM. Cytosolic free Ca2+ was significantly higher in platelets of hypertensive patients than in those of normotensive subjects (241 +/- 9 versus 192 +/- 7 nmol/l, n = 58 and 57, respectively P less than 0.001). When all 115 subjects were included, there was a significant correlation between cytosolic free Ca2+ and systolic or diastolic blood pressure (r = 0.262, P less than 0.0025 and r = 0.251, P less than 0.0025, respectively). Intracellular Quin 2 concentration was measured to evaluate the formaldehyde production (a product of Quin 2/AM hydrolysis which has been described as reducing the adenosine triphosphate (ATP) production). The Quin 2 concentrations in platelets of the two groups of subjects were observed to be similar (0.41 +/- 0.03 versus 0.38 +/- 0.03 mmol/l, n = 8 and 7 for hypertensives and normotensives, respectively). The effects of prostaglandin E1 (PGE1), an adenylate cyclase stimulator, on cytosolic free Ca2+ were studied. The presence of 10(-7) mol/l PGE1 lowered the Ca2+ in platelets of hypertensive patients only, suppressing the difference between the two groups.
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PMID:Increased platelet cytosolic free calcium concentration in essential hypertension. 379 31

The formaldehyde method was used to examine the effects of clonidine and methoxamine on IgE-mediated 14C-serotonin release from rat mast cells in vitro. Clonidine (10(-11) -10(-8) M) caused dose-related enhancement of the mediator release 7 min after the antigen challenge; yohimbine (10(-6) M) blocked this enhancement by clonidine (10(-6) M), but prazosin (10(-6) M) did not. Methoxamine did not enhance this immunological release reaction at concentrations up to 10(-6) M. PGE1 (2 X 10(-8) -2 X 10(-5) M), isoproterenol (10(-10) -10(-8) M), dopamine (4 X 10(-8) -4 X 10(-8) M) and aminophylline (6 X 10(-6) -6 X 10(-4) M) caused dose-related inhibition of this mediator release 1 min after antigen challenge. Clonidine (10(-13) -10(-12) M), but not methoxamine (10(-8) -10(-6) M), reversed dose-dependently this inhibition of mast cells by PGE1 (2 X 10(-6) M), isoproterenol (10(-8) M), dopamine (4 X 10(-6) M); yohimbine (10(-8) M) antagonized this reversing action of clonidine (10(-12) M), but prazosin (10(-10) M) did not. Neither clonidine (10(-14) -10(-11) M) nor methoxamine (10(-8) -10(-6) M) reversed the inhibitory action of aminophylline (2 X 10(-4) M). These results suggests that clonidine enhances IgE-mediated 14C-serotonin release from rat mast cells and also antagonizes the inhibition of mast cells by PGE1, isoproterenol and dopamine, but not by aminophylline in this immunological reaction through alpha 2-adrenergic receptors, and that the inhibition of adenylate cyclase of mast cells is one of the biochemical actions of alpha 2-adrenergic mechanisms.
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PMID:Modulation by alpha 2-adrenergic stimulation of IgE-mediated 14C-serotonin release from rat mast cells. 613 38

A cytochemical procedure for the localization of adenylate cyclase with Sr2+ as the capture ion and adenylyl imidodiphosphate as the specific substrate was evaluated in the rat pancreas. Incubation medium was unaffected by the addition of 5 mM strontium ions but became turbid in the presence of lead or strontium plus 10 mM NaF. Tissues were prefixed in 2% formaldehyde/0.5% glutaraldehyde and incubated, and the cytochemical precipitate was converted to the Pb2+ salt. Enzymatic activity was demonstrated on the plasma membrane of pancreatic acinar cells and responded to stimulation by secretin. Controls frequently contained Pb2+ sequestered in mitochondria, but otherwise only a few randomly distributed grains were observed. The controls were 1) omission of substrate from the medium; 2) incubation of tissue for 1 min in complete medium; and 3) tissue previously inactivated by microwave irradiation and incubated for 30 min in complete medium including secretin.
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PMID:Cytochemical demonstration of adenylate cyclase with strontium chloride in the rat pancreas. 618

The temporal relationship between redistribution of receptors to lutropin (luteinizing hormone)/human chorionic gonadotropin in cultured rat ovarian granulosa cells and the cellular response to hormonal challenge were studied. Visualization of receptor-bound human chorionic gonadotropin by indirect immunofluorescence, with hormone-specific antibodies after fixation with 2% formaldehyde, revealed the existence of small clusters around the entire cell circumference 5--20 min after exposure to the hormone at 37 degrees C. Such small receptor aggregates were also evident if hormone incubation was at 4 degrees C or if cells were fixed with 2% formaldehyde before incubation. Larger clusters were evident after prolonged incubation with the hormone (2--4 hr) at 37 degrees C. The later change coincided with diminished cyclic AMP accumulation in respose to challenge with fresh hormone. When the fixation step was omitted and antibodies to human chorionic gonadotropin were applied after hormonal binding, acceleration of both receptor clustering and the desensitization process was observed. This maneuver also induced capping of the hormone receptors. In contrast, monovalent Fab' fragments of the antibodies were without effect. Internalization of the bound hormone in lysosomes, and subsequent degradation, was evident 8 hr after hormonal application and was not accelerated by the antibodies. It is suggested that clustering of the luteinizing hormone receptors may play a role in cellular responsiveness to the hormone. Massive aggregation of the receptors may desensitize the cell by interferring with coupling to adenylate cyclase.
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PMID:Aggregation of luteinizing hormone receptors in granulosa cells: a possible mechanism of desensitization to the hormone. 625 59

The formaldehyde method was used to examine the interactions of morphine with PGE1, isoproterenol, dopamine and aminophylline in rat mast cells by their effects on IgE-mediated 14C-serotonin release. PGE1 (2 x 10(-8) -2 x 10(-5) M), isoproterenol (10(-10) -10(-8) M), dopamine (4 x 10(-8) -4 x 10(-6) M) and aminophylline (6 x 10(-6) -6 x 10(-4) M) caused dose-related inhibition of the mediator release 1 min after an antigen challenge, and propranolol (10(-7) M) blocked the inhibition by isoproterenol (10(-8) M) but not that by dopamine (4 x 10(-6) M), while haloperidol (4 x 10(-6) M) blocked that by dopamine (4 x 10(-6) M) but not that by isoproterenol (10(-8) M). Morphine (3 x 10(-7) -3 x 10(-5) M) reversed the inhibitory effects of PGE1 (2 x 10(-6) M), isoproterenol (10(-8) M) and dopamine (4 x 10(-6) M) dose-dependently and stereospecifically; naloxone (2 x 10(-4) M) antagonized these reversing actions of morphine (3 x 10(-5) M). Morphine (10(-6) -10(-4) M) did not reverse the inhibitory action of aminophylline (6 x 10(-4) M). These results suggest that the inhibitory responses of mast cells to PGE1, isoproterenol and dopamine but not to aminophylline in immunological mediator release were reversed by morphine through opioid receptors, and that the inhibition of adenylate cyclase in mast cells is one of the biochemical actions of morphine.
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PMID:Interactions of morphine with PGE1, isoproterenol, dopamine and aminophylline in rat mast cells; their effect on IgE-mediated 14C-serotonin release. 668 67

Pituitary adenylate cyclase-activating peptide (PACAP)-like immunoreactivity was demonstrated by immunocytochemistry together with calcitonin gene-related peptide (CGRP)-like immunoreactivity in small to medium-sized neurons in the trigeminal ganglion and in nerve fibers in the iris, ciliary body, cornea, choroid and sclera of the rabbit eye. The regional distribution of PACAP-27- and PACAP-38-like immunoreactivity in the eye was studied by radioimmunoassay: the highest concentrations were found in the iris sphincter and ciliary body. The distribution pattern resembled that of CGRP-like immunoreactivity, which is a well-known constituent of sensory C-fibre neurons. Intravitreal injection of PACAP-27 or PACAP-38 induced conjunctival hyperemia, swelling of the anterior segment of the eye, miosis and breakdown of the blood-aqueous barrier, manifested as a marked aqueous flare response. Tetrodotoxin pretreatment inhibited the conjunctival hyperemia, the swelling of the anterior segment of the eye, and the miosis but not the aqueous flare response. The concentration of PACAP-like immunoreactivity in the aqueous humor was increased greatly following infrared irradiation of the iris, topical application of formaldehyde to the cornea, or intravitreal injection of endotoxin or bovine serum albumin. Also the concentration of CGRP-like immunoreactivity in the aqueous humor was increased greatly. Both in vivo and in vitro studies showed that capsaicin caused a parallel release of PACAP-like immunoreactivity and CGRP-like immunoreactivity from the uvea. Injection of PACAP-27 and PACAP-38 resulted in the release of CGRP-like immunoreactivity (and PACAP-like immunoreactivity) into the aqueous humor and PACAP-27 and PACAP-38 were also found to evoke tachykinin-mediated contractions of the isolated iris sphincter muscle, indicating that PACAP induces positive feedback on C-fibres. Thus, PACAP is a sensory neuropeptide in the eye. Since the PACAP-induced ocular responses mimicked the symptoms of inflammation, and since the PACAP-like immunoreactivity concentration in the aqueous humor was greatly increased following noxious stimulation, we suggest that it takes part in the inflammatory responses of the rabbit eye.
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PMID:Distribution and effects of pituitary adenylate cyclase-activating peptide in the rabbit eye. 863 27

NAVA's acellular pertussis vaccine is based on highly purified pertussis toxin (PT) inactivated with H(2)O(2). PT was analysed using advanced biochemical methodology including mass spectroscopy (LC/MS), yielding mass and peptide mapping information on the subunits. Pertactin, adenylate cyclase, and Fim 1, 2 were below detection levels and only trace amounts of filamentous haemagglutinin (FHA) have been identified as a minor impurity. The vaccine does not induce anti-FHA antibodies during the course of a 3-dose primary immunization series in infants. B and T cell epitopes are preserved to a higher extent after H(2)O(2)detoxification when compared with chemical inactivation with formaldehyde, thus providing new information explaining why vaccines employing formaldehyde detoxified PT may need additional pertussis components added to induce high levels of protection. Anti-PT antibodies generated by NAVA diphtheria, tetanus, and acellular pertussis vaccine (DTaP) showed a positive correlation with protection against WHO-defined pertussis. The safety profiles for these vaccines showed low reactogenicity with no serious adverse events due to the vaccines.
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PMID:DTaP vaccines from north american vaccine (NAVA): composition and critical parameters. 1060 Jan 91

We have examined the development of the dopaminergic system of the guinea pig retina, a species in which retinal neuronal and synaptic differentiation occurs largely in utero. Fetal animals aged 42-69 days (full term), neonates, postnatal (pn) animals to 12 weeks, and mature animals were studied to determine retinal dopamine (DA) storage, metabolism (DOPAC), in vitro tyrosine hydroxylase (TH) activity, postsynaptic target activation (cAMP stimulation) and localization (formaldehyde-induced histofluorescence). DA-stimulated adenylate cyclase at 42 days of gestation was threefold over basal activity, preceding the onset of the accumulation of DA and DOPAC at 45 days, and the initial localization of DA in cell perikarya at 47 days and in processes at 50 days. At birth DA and DOPAC levels were 45 and 37%, respectively, of adult levels. DA levels remained stable during the first few days pn, although in vitro TH activity was capable of stimulation by light in the neonate as in the mature animal. DA and TH activity increased from 1 week pn to reach adult levels by 10 weeks pn. Although a significant degree of development of the dopaminergic neurotransmitter system in the guinea pig occurs before birth the attainment of a fully mature system postnatally may require normal photic stimulation of physiologic activity.
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PMID:The ontogenesis of the dopaminergic cell in the pre- and postnatal guinea pig retina. 2487 97


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