The effects of serotonin and dopamine on salivary secretion by isolated cockroach salivary glands

1996 ◽  
Vol 199 (2) ◽  
pp. 407-413 ◽  
Author(s):  
F Just ◽  
B Walz
Keyword(s):  
Salivary Glands ◽  
Periplaneta Americana ◽  
Morphological Changes ◽  
Salivary Secretion ◽  
Dependent Manner ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
Protein Rich ◽  
Dose Dependent ◽  
Stimulation Of

We have studied the effects of 3-hydroxytyramine (dopamine) and 5-hydroxytryptamine (serotonin) on (1) the rates of salivation from isolated salivary glands of the cockroach Periplaneta americana, (2) the protein content of the saliva, and (3) the ultrastructure of the salivary gland epithelium. The rates of neurotransmitter-induced salivation varied in a dose-dependent manner within the concentration range 10(-9) to 10(-4) mol l-1. Half-maximal secretory rates were induced by 6x10(-7) mol l-1 serotonin and 1.1x10(-7) mol l-1 dopamine. Stimulation of the glands by serotonin resulted in the production of a protein-rich saliva, whereas saliva was protein-free after stimulation by dopamine. Electron microscopic studies revealed that the central cells, which are believed to produce the proteinaceous components of the saliva, secrete their vesicular content after stimulation by 10(-6) mol l-1 serotonin for 20 min. In contrast, no morphological changes could be detected after stimulation by 10(-6) mol l-1 dopamine. These data indicate that dopamine stimulates only the secretion of the fluid component of the saliva, whereas serotonin is necessary to stimulate secretion of the proteinaceous components.

Electron Microscopic study of the polymyxin treated vibrio cholerae cells

1990 ◽  
Vol 48 (3) ◽  
pp. 642-643
Author(s):  
Tapas Kumar Mandal
Keyword(s):  
Vibrio Cholerae ◽  
Morphological Changes ◽  
Indian Subcontinent ◽  
Analytical Techniques ◽  
Polymyxin B ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
Bacterial Organism ◽  
Polypeptide Antibiotic ◽  
Dose Dependent

Infections by Vibrio Cholerae (a gram-negative bacterial organism) in the Indian subcontinent are frequently encoutered. The polypeptide antibiotic polymyxin-B (PB) is a clinically important antibiotic which is used to treat infections caused by a number of gr am-negative bacteria. It has been observed that PB causes disruption of u U1rastructure of outer membrane (OW) , as revealed by the electron microscopic studies for a number of bacteria, through the formation of blebs and crenations (finger-like structures) on the OM . In this context, it is relevant to look specifically at the morphological changes induced by PB on Vibrio cells. PB produces dose dependent changes in the surface topography of pathogenic Vibrio cholerae cells. The susceptibilities of various vibrio strains to PB are also studied through analytical techniques.

Synaptic Responses of Neurons Controlling the Parotid and von Ebner Salivary Glands in Rats to Stimulation of the Solitary Nucleus and Tract

2008 ◽  
Vol 99 (3) ◽  
pp. 1267-1273 ◽  
Author(s):  
Takeshi Suwabe ◽  
Hideyuki Fukami ◽  
Robert M. Bradley
Keyword(s):  
Salivary Glands ◽  
Sensory Information ◽  
Salivary Secretion ◽  
Afferent Input ◽  
Membrane Hyperpolarization ◽  
Neuron Response ◽  
Glutamate Receptor Antagonists ◽  
Autonomic Neurons ◽  
Reflex Stimulation ◽  
Stimulation Of

Salivary secretion results from reflex stimulation of autonomic neurons via afferent sensory information relayed to neurons in the rostral nucleus of the solitary tract (rNST), which synapse with autonomic neurons of the salivatory nuclei. We investigated the synaptic properties of the afferent sensory connection to neurons in the inferior salivatory nucleus (ISN) controlling the parotid and von Ebner salivary glands. Mean synaptic latency recorded from parotid gland neurons was significantly shorter than von Ebner gland neurons. Superfusion of GABA and glycine resulted in a concentration-dependent membrane hyperpolarization. Use of glutamate receptor antagonists indicated that both AMPA and N-methyl-d-aspartate (NMDA) receptors are involved in the evoked excitatory postsynaptic potentials (EPSPs). Inhibitory postsynaptic potential (IPSP) amplitude increased with higher intensity ST stimulation. Addition of the glycine antagonist strychnine did not affect the amplitude of the IPSPs significantly. The GABAA receptor antagonist, bicuculline (BMI) or mixture of strychnine and BMI abolished the IPSPs in all neurons. IPSP latency was longer than EPSP latency, suggesting that more than one synapse is involved in the inhibitory pathway. Results show that ISN neurons receive both excitatory and inhibitory afferent input mediated by glutamate and GABA respectively. The ISN neuron response to glycine probably derives from descending connections. Difference in the synaptic characteristics of ISN neurons controlling the parotid and von Ebner glands may relate to the different function of these two glands.

scholarly journals Adrenaline Stimulation of Phospholipid Metabolism in Adipocyte Ghosts

1987 ◽  
Vol 40 (4) ◽  
pp. 405
Author(s):  
David Mann ◽  
Audrey M Bersten
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Linoleic Acid ◽  
Adenylate Cyclase ◽  
Phospholipid Metabolism ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Membrane Phospholipids ◽  
Dose Dependent ◽  
Stimulation Of

The incorporation of long-chain fatty acids into phospholipids has been detected in adipocyte ghosts that were incubated with [1_14 C] stearic, [1_14 C] linoleic or [l_14C] arachidonic acid. Adrenaline and adenosine activated this incorporation within 15 s of exposure of the ghosts to the hormones and the response was dose dependent. Maximum incorporation of labelled linoleic acid occurred at 10-5 M adrenaline and 10-7 M adenosine. The a-agonist phenylephrine and the ~-agonist isoproterenol were also shown to stimulate the incorporation of fatty acid in a dose dependent manner. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were each labelled preferentially with linoleic or arachidonic acid. p-Bromophenacylbromide, quinacrine and centrophenoxine inhibited the adrenaline-stimulated incorporation of fatty acids into ghost membrane phospholipids, and p-bromophenacylbromide also reduced the activation of adenylate cyclase by adrenaline. NaF, an activator of adenylate cyclase, like adrenaline, stimulated the incorporation of linoleic acid into ghost membrane phospholipids.

scholarly journals Proteoglycan and glycosaminoglycan synthesis in embryonic mouse salivary glands: effects of beta-D-xyloside, an inhibitor of branching morphogenesis.

1983 ◽  
Vol 96 (5) ◽  
pp. 1443-1450 ◽  
Author(s):  
H A Thompson ◽  
B S Spooner
Keyword(s):  
Salivary Glands ◽  
Dermatan Sulfate ◽  
Branching Morphogenesis ◽  
Proteoglycan Synthesis ◽  
Embryonic Mouse ◽  
Glycosaminoglycan Synthesis ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent ◽  
Stimulation Of

The proteoglycans and glycosaminoglycans synthesized by embryonic mouse salivary glands during normal morphogenesis and in the presence of beta-xyloside, an inhibitor of branching morphogenesis, have been partially characterized. Control and rho-nitrophenyl-beta-D-xyloside-treated salivary rudiments synthesize proteoglycans that are qualitatively similar, based on mobility on Sepharose CL-4B under dissociative conditions and glycosaminoglycan composition. However, beta-xyloside inhibits total proteoglycan-associated glycosaminoglycan synthesis by 50%, and also stimulates synthesis of large amounts of free chondroitin (dermatan) sulfate. This free glycosaminoglycan accounts for the threefold stimulation of total glycosaminoglycan synthesis in beta-xyloside-treated cultures. Several observations suggest that the disruption of proteoglycan synthesis rather than the presence of large amounts of free glycosaminoglycan is responsible for the inhibition of branching morphogenesis. (a) We have been unable to inhibit branching activity by adding large amounts of chondroitin (dermatan) sulfate, extracted from beta-xyloside-treated cultures, to the medium of salivary rudiments undergoing morphogenesis. (b) In the range of 0.1-0.4 mM beta-xyloside, the dose-dependent inhibition of branching morphogenesis is directly correlated with the inhibition of proteoglycan synthesis. The stimulation of free glycosaminoglycan synthesis is independent of dose in this range, since stimulation is maximal even at the lowest concentration used, 0.1 mM. The data strongly suggest that the inhibition of branching morphogenesis is caused by the disruption of proteoglycan synthesis in beta-xyloside-treated salivary glands.

Effect of galanin on glucose-, arginine-, or potassium-stimulated insulin release

1989 ◽  
Vol 256 (5) ◽  
pp. E619-E623
Author(s):  
T. Yoshimura ◽  
J. Ishizuka ◽  
G. H. Greeley ◽  
J. C. Thompson
Keyword(s):  
Insulin Release ◽  
High Glucose ◽  
Second Phase ◽  
Dependent Manner ◽  
Perfused Pancreas ◽  
Isolated Perfused Pancreas ◽  
Second Phases ◽  
High Concentrations ◽  
Dose Dependent ◽  
Stimulation Of

We have examined the effect of galanin infusion on glucose-stimulated release of insulin from the isolated perfused pancreas of the rat to better characterize the effect of galanin on the first and second phases of insulin release. The effects of galanin on insulin release stimulated by L-arginine or high concentrations of potassium were also examined. When perfusion of galanin was started 4 min before the start of perfusion of high glucose (16.7 mM), galanin (10(-8)-10(-11) M) inhibited both the first and second phases of insulin release in a dose-dependent manner. When perfusion of galanin (10(-8) or 10(-9) M) was started simultaneously with high glucose (16.7 mM), only the second phase of insulin release was suppressed (P less than 0.05). Galanin (10(-9) M) failed to inhibit insulin release stimulated by L-arginine (10 and 5 mM) or potassium (25 and 20 mM). These findings suggest that the inhibitory action of galanin on glucose-stimulated insulin release is exerted on early intracellular events that occur during the stimulation of insulin release and that are common to both phases. Because galanin does not inhibit insulin release stimulated by L-arginine or potassium, galanin may inhibit glucose-stimulated closure of potassium channels.

Physiological concentrations of insulin and T3 stimulate 3T3-L1 adipocyte acyl-CoA synthetase gene transcription

1996 ◽  
Vol 270 (5) ◽  
pp. E873-E881 ◽  
Author(s):  
M. S. Kansara ◽  
A. K. Mehra ◽  
J. Von Hagen ◽  
E. Kabotyansky ◽  
P. J. Smith
Keyword(s):  
Gene Transcription ◽  
Fold Increase ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Reciprocal Regulation ◽  
Stearoyl Coa Desaturase ◽  
Dose Dependent ◽  
Long Chain ◽  
Stimulation Of

Acyl-CoAsynthetase (ACS) is a key gene for cellular utilization of long-chain fatty acids. We characterized its regulation by physiological concentrations of insulin that acutely regulate metabolism. Our results demonstrate that subnanomolar insulin rapidly and maximally stimulates ACS gene transcription in the absence of protein synthesis; 0.5 nM insulin produced a 2.3 +/- 0.1-fold increase in ACS mRNA levels and induced ACS gene transcription 2.4 +/- 0.3-fold. The insulin sensitivity of ACS was compared with lipoprotein lipase (LPL) and stearoyl-CoA desaturase-1 (SCD-1), which were both less sensitive to insulin. Physiological triiodothyronine (10 nm) also induced ACS mRNA 2.4 +/- 0.1-fold and gene transcription 2.8 +/- 0.3-fold and coordinately induced LPL and SCD-1 mRNA and gene transcription. Because insulin and adenosine 3',5'-cyclic monophosphate often regulate genes involved in lipid and carbohydrate metabolism in a reciprocal manner, we evaluated effects of 1-methyl-3-isobutylxanthine (MIX).ACS mRNA levels were strongly downregulated by MIX in a dose-dependent manner, and ACS gene transcription inhibited in a coordinate manner with LPL and SCD-1. These data demonstrate a uniquely sensitive pattern of stimulation of ACS gene transcription by insulin with reciprocal regulation by MIX, and they suggest a significant role for ACS as a tightly regulated “gatekeeper” gene participating in the control of adipocyte metabolism.

Antral gland cell column: a method for studying release of gastric hormones

1983 ◽  
Vol 245 (4) ◽  
pp. G463-G469
Author(s):  
B. Richelsen ◽  
J. F. Rehfeld ◽  
L. I. Larsson
Keyword(s):  
In Vitro Release ◽  
Dependent Manner ◽  
Gastrin Release ◽  
Cell Column ◽  
Independent Manner ◽  
Response Characteristics ◽  
Dose Dependent ◽  
Vitro Release ◽  
Stimulation Of

A technique for studying in vitro release of gastric hormones has been developed. The system utilizes nonenzymatically isolated antropyloric glands from humans or rats, which are perifused in a Bio-Gel P-2 column. The system permits the study of kinetics and dose-response characteristics using the glands as their own control. The glands were stimulated with carbachol and bombesin, and the antral peptides gastrin and somatostatin were measured. Bombesin and carbachol both evoked a dose-dependent stimulation of gastrin release, beginning at below 10(-10) M (bombesin) and 10(-7) M (carbachol). Carbachol inhibited the release of somatostatin in a dose-dependent manner, being maximally effective at 10(-6) M and then producing 60% inhibition of somatostatin release. Bombesin was without effect on antropyloric somatostatin release. These data suggest that the gastrin-stimulating effect of carbachol is partially or totally due to inhibition of somatostatin release, whereas bombesinergic stimulation of gastrin release must work in an independent manner. In addition, data on the effects of these substances on the release of gastrin and ACTH-like peptides from human antropyloric glands are presented. Due to the absence of local neural reflexes, this system is a useful supplement to the isolated perfused stomach model.

scholarly journals Use of a model to understand the synergies underlying the antibacterial mechanism of H2O2-producing honeys

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria Masoura ◽  
Paolo Passaretti ◽  
Tim W. Overton ◽  
Pete A. Lund ◽  
Konstantinos Gkatzionis
Keyword(s):  
Gluconic Acid ◽  
Morphological Changes ◽  
Dependent Manner ◽  
Antibacterial Mechanism ◽  
General Stress Response ◽  
E Coli ◽  
Simple Model System ◽  
Ancient Times ◽  
K 12 ◽  
Dose Dependent

Abstract Honey has been valued as a powerful antimicrobial since ancient times. However, the understanding of the underlying antibacterial mechanism is incomplete. The complexity and variability of honey composition represent a challenge to this scope. In this study, a simple model system was used to investigate the antibacterial effect of, and possible synergies between, the three main stressors present in honey: sugars, gluconic acid, and hydrogen peroxide (H2O2), which result from the enzymatic conversion of glucose on honey dilution. Our results demonstrated that the synergy of H2O2 and gluconic acid is essential for the antibacterial activity of honey. This synergy caused membrane depolarization, destruction of the cell wall, and eventually growth inhibition of E. coli K-12. The presence of H2O2 stimulated the generation of other long-lived ROS in a dose-dependent manner. Sugars caused osmosis-related morphological changes, however, decreased the toxicity of the H2O2/gluconic acid. The susceptibility of catalase and general stress response sigma factor mutants confirmed the synergy of the three stressors, which is enhanced at higher H2O2 concentrations. By monitoring cellular phenotypic changes caused by model honey, we explained how this can be bactericidal even though the antimicrobial compounds which it contains are at non-inhibitory concentrations.

scholarly journals Anticancer Potential of Fruit Extracts from Vatica diospyroides Symington Type SS and Their Effect on Program Cell Death of Cervical Cancer Cell Lines

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Atchara Chothiphirat ◽  
Kesara Nittayaboon ◽  
Kanyanatt Kanokwiroon ◽  
Theera Srisawat ◽  
Raphatphorn Navakanitworakul
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Morphological Changes ◽  
Annexin V ◽  
Siha Cell ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Cervical Cancer Cells ◽  
Dose Dependent

Vatica diospyroides Symington is locally known as Chan-Ka-Pho in Thailand. Ancient people have used it as therapeutic plant for cardiac and blood tonic cure. The purpose of this study was to investigate the potential cytotoxicity and selectivity of the extracts from V. diospyroides type SS fruit on cervical cancer HeLa and SiHa cell lines and to examine its underlying mechanism of action. MTT assay revealed that the extracts showed inhibition of cell survival in a dose-dependent manner and exhibited highly cytotoxic activity against both HeLa and SiHa cells with IC50 value less than 20 μg/mL along with less toxicity against L929 cells. Acetone cotyledon extract (ACE) showed the best selectivity index value of 4.47 (HeLa) and 3.51 (SiHa). Distinctive morphological changes were observed in ACE-treated cervical cancer cells contributing to apoptosis action. Flow cytometry analysis with Annexin V-FITC and PI staining precisely indicated that ACE induced apoptosis in HeLa and SiHa cell lines in a dose-dependent manner. Treatment of ACE with half IC50 caused DNA fragmentation and also activated increasing of bax and cleaved caspase-8 protein in HeLa cells after 48 h exposure. The results suggest that ACE has potent and selective cytotoxic effect against cervical cancer cells and the potential to induce bax and caspase-8-dependent apoptosis. Hence, the ACE could be further exploited as a potential lead in cancer treatment.

Secretory patterns of 1α-hydroxycorticosterone in the isolated perifused interrenal gland of the dogfish, Scyliorhinus canicula

1990 ◽  
Vol 5 (1) ◽  
pp. 55-60 ◽  
Author(s):  
L. B. O'Toole ◽  
K.J. Armour ◽  
C. Decourt ◽  
N. Hazon ◽  
B. Lahlou ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Significant Rise ◽  
Dependent Manner ◽  
Steroid Production ◽  
Secretory Rate ◽  
Scyliorhinus Canicula ◽  
Interrenal Gland ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT An isolated in-vitro perifused interrenal gland preparation from the dogfish Scyliorhinus canicula was used to study production of quantitatively the major corticosteroid 1α-hydroxycorticosterone (1α-OH-B), measured by radioimmunoassay. Basal secretory rates were 877·1 ± 145 (s.e.m.) fmol/mg per 15 min (n=14) and the preparation remained viable for up to 22 h, as reflected in a brisk response to 10 μm cyclic AMP (cAMP) after this time. Steroid production responded in a dose-dependent manner to porcine ACTH, with 10 μm producing a maximum stimulation of 225% above the basal secretory rate. cAMP (10 μm) produced an increase of 278% above basal, while 1 μm forskolin increased basal secretory rates by 127%. [Val5]- and [Ile5]-angiotensin II (0·1 μm) increased 1α-OH-B production by 120 and 372% respectively over basal secretory rates. Increasing the concentration of K+ in the perfusate from 8 mm to 12, 18, 28 and 40 mm produced a significant rise only at 28 mm. Alterations in the concentration of Na+ and osmolarity of the perifusion medium had inconsistent effects on steroid production. Increased concentrations of urea (from 360 to 720 mm) increased the basal secretory rate by 121%, whilst reducing the concentration of urea (from 360 to 90 mm) had no effect.

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