scholarly journals Effect of Noni (Morinda citrifoliaLinn.) Fruit and Its Bioactive Principles Scopoletin and Rutin on Rat Vas Deferens Contractility: AnEx VivoStudy

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Vijayapandi Pandy ◽  
Megala Narasingam ◽  
Thubasni Kunasegaran ◽  
Dharmani Devi Murugan ◽  
Zahurin Mohamed
Keyword(s):  
Vas Deferens ◽  
Contractile Response ◽  
Rat Vas Deferens ◽  
Morinda Citrifolia ◽  
Dependent Manner ◽  
Per Se ◽  
High Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Agonistic Effect

This study examined the effect of methanolic extract ofMorinda citrifoliaLinn. (MMC) and its bioactive principles, scopoletin and rutin, on dopamine- and noradrenaline-evoked contractility in isolated rat vas deferens preparations. MMC (1–40 mg/mL), scopoletin (1–200 μg/mL), and rutin hydrate (0.6–312.6 μg/mL) dose-dependently inhibited the contractility evoked by submaximal concentrations of both dopamine and noradrenaline, respectively. Haloperidol and prazosin, reference dopamine D2, andα1-adrenoceptors antagonists significantly reversed the dopamine- and noradrenaline-induced contractions, respectively, in a dose-dependent manner. Interestingly, MMCper seat higher doses (60–100 mg/mL) showed dose-dependent contractile response in rat vas deferens which was partially inhibited by high doses of haloperidol but not by prazosin. These results demonstrated the biphasic effects of MMC on dopaminergic system; that is, antidopaminergic effect at lower concentrations (<40 mg/mL) and dopaminergic agonistic effect at higher concentrations (>60 mg/mL). However, similar contractile response at high doses of scopoletin (0.5–5 mg/mL) and rutin hydrate (0.5–5 mg/mL)per sewas not observed. Therefore, it can be concluded that the bioactive principles of MMC, scopoletin, and rutin might be responsible for the antidopaminergic and antiadrenergic activities of MMC.

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

Intracerebroventricular injection of prostaglandin E2 increases splenic sympathetic nerve activity in rats

1995 ◽  
Vol 269 (3) ◽  
pp. R662-R668 ◽  
Author(s):  
T. Ando ◽  
T. Ichijo ◽  
T. Katafuchi ◽  
T. Hori
Keyword(s):  
Prostaglandin E2 ◽  
Sympathetic Nerve ◽  
Time Course ◽  
Sympathetic Nerve Activity ◽  
Dependent Manner ◽  
Central Administration ◽  
Nerve Activity ◽  
High Doses ◽  
Alpha Chloralose ◽  
Dose Dependent

The effects of central administration of prostaglandin E2 (PGE2) and its selective agonists on splenic sympathetic nerve activity (SNA) were investigated in urethan- and alpha-chloralose-anesthetized rats. An intra-third-cerebroventricular (13V) injection of PGE2 (0.1-10 nmol/kg) increased splenic SNA in a dose-dependent manner. An I3V injection of an EP1 agonist, 17-phenyl-omega-trinor PGE2 (1-30 nmol/kg), also resulted in a dose-dependent increase in splenic SNA, with a time course similar to that of PGE2-induced responses. In contrast, EP2 agonists, butaprost (10-100 nmol/kg I3V) and 11-deoxy-PGE1 (10-100 nmol/kg I3V), had no effect on splenic SNA. An I3V injection of M & B-28767 (an EP3/EP1 agonist, EP3 >> EP1) increased splenic SNA only at high doses (10-100 nmol/kg). Pretreatment with an EP1 antagonist, SC-19220 (200 and 500 nmol/kg), completely blocked the responses of splenic SNA to PGE2 (0.1 nmol/kg) and M & B-28767 (10 nmol/kg), respectively. These findings indicate that brain PGE2 increases splenic SNA through its action on EP1 receptors.

The role of transmembrane sodium gradient in rabbit ileal smooth muscle: Utilization of harmaline

1985 ◽  
Vol 5 (8) ◽  
pp. 667-671 ◽  
Author(s):  
M. S. Suleiman
Keyword(s):  
Smooth Muscle ◽  
Contractile Response ◽  
Sodium Concentration ◽  
Exchange Mechanism ◽  
Dependent Manner ◽  
Sodium Gradient ◽  
Extracellular Sodium ◽  
Dose Dependent

Decreasing extracellular sodium concentration was found to produce a contractile response of rabbit ileal smooth muscle. As the concentration decreases, the amplitude of contraction increases, thus producing a dose-dependent curve. Harmaline, a competitor for sodium, was found to inhibit the sodium gradient-dependent contractions in a dose-dependent manner. The results are interpreted as harmaline inhibiting a Na–Ca exchange mechanism present in ileal smooth muscle.

Effect of ethyl alcohol on motor function in canine stomach

1992 ◽  
Vol 262 (2) ◽  
pp. G223-G230
Author(s):  
L. C. Knight ◽  
A. H. Maurer ◽  
R. Wikander ◽  
B. Krevsky ◽  
L. S. Malmud ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Solid Food ◽  
Blood Levels ◽  
Lag Phase ◽  
Dependent Manner ◽  
Solid Meal ◽  
The Mean ◽  
High Doses ◽  
Mean Time ◽  
Dose Dependent

The aim of this study was to elucidate the effects of ethanol on gastric emptying and the trituration of solid food. With the use of a noninvasive physiological imaging technique, gastric processing of a radiolabeled solid meal was evaluated in unanesthetized dogs which ingested 6-8% ethanol solutions or received intravenous alcohol before the meal. Oral alcohol (resulting in blood levels up to 174 mg/dl) decreased the amplitude of antral contractions or completely abolished them. Alcohol did not significantly affect the fundamental frequency of contractions except at high doses, at which contractions were abolished. Alcohol lengthened the mean time to 50% of gastric emptying in a dose-dependent manner, from 132 +/- 3 min without alcohol to 160 +/- 10 min with oral alcohol at blood levels of 80-120 mg/dl (P less than 0.05). This was manifested by a lengthening of the lag phase, but there was no effect on the terminal slope of emptying (emptying rate) of the processed meal. At equal blood levels up to 120 mg/dl, orally administered alcohol had a more pronounced effect than intravenous alcohol. These data suggest that even low doses of dilute alcohol affect the ability of the antrum to process solid food and thereby contribute to impairment of gastric emptying.

Effects of cholecystokinin-octapeptide on gastric motility of anesthetized dogs

1986 ◽  
Vol 251 (5) ◽  
pp. G678-G681 ◽  
Author(s):  
A. Kuwahara ◽  
K. Ozawa ◽  
N. Yanaihara
Keyword(s):  
Smooth Muscle ◽  
Gastric Motility ◽  
Contractile Response ◽  
Smooth Muscle Contraction ◽  
Dependent Manner ◽  
Local Effects ◽  
Cholecystokinin Octapeptide ◽  
Gastric Smooth Muscle ◽  
Anesthetized Dogs ◽  
Dose Dependent

The present experiments examined the local effects of cholecystokinin-octapeptide (CCK-8) and related peptides on gastric motility of anesthetized dogs. Peptides were injected through the gastroepiploic artery at doses of 1.0, 2.5, 5.0, 10.0, and 20.0 ng/ml. CCK-8 and its analogues (Glt-CCK-8, pGlu-CCK-8, and Suc1-MePhe8-CCK-7) increased gastric smooth muscle contraction in a dose-dependent manner. ED50 of CCK-8 was 2.97 +/- 0.63 ng/ml. Administration of atropine (100–200 micrograms/kg) inhibited the effects of both CCK-8 and pentagastrin; however, hexamethonium (5 mg/kg) failed to block the contractile response induced by CCK-8 and pentagastrin. These results indicate that CCK-8 and related peptides can act as local modulators in controlling the neural regulation of gastric motility.

The effects of the ionophore A-23187 on the rat vas deferens

1983 ◽  
Vol 61 (1) ◽  
pp. 97-101 ◽  
Author(s):  
M. W. Warenycia ◽  
M. M. Vohra
Keyword(s):  
Vas Deferens ◽  
Calcium Ionophore ◽  
Rat Vas Deferens ◽  
Adrenergic Nerves ◽  
Time Dependent ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
A 23187 ◽  
Endogenous Noradrenaline ◽  
Rhythmic Contractions

The calcium ionophore A-23187 induced spontaneous, rhythmic contractions in the rat isolated vas deferens in a concentration-dependent manner. Contractions were blocked by phentolamine and were abolished following pretreatment with reserpine. In tissues preloaded with [3H]noradrenaline, A-23187 (10 μM) caused a time-dependent increase in the release of tritium. The findings suggest that A-23187-induced contractions in the rat vas deferens are secondary to the release of endogenous noradrenaline from the adrenergic nerves, as are contractions induced in this preparation by X-537A (another calcium ionophore) described earlier by other investigators.

The vagus nerve in the thermoregulatory response to systemic inflammation

1997 ◽  
Vol 273 (1) ◽  
pp. R407-R413 ◽  
Author(s):  
A. A. Romanovsky ◽  
C. T. Simons ◽  
M. Szekely ◽  
V. A. Kulchitsky
Keyword(s):  
Intravenous Injection ◽  
Systemic Inflammation ◽  
Second Phase ◽  
Thermoregulatory Response ◽  
Cool Environment ◽  
Bolus Intravenous Injection ◽  
High Doses ◽  
Colonic Temperature ◽  
Dose Dependent ◽  
Higher Doses

Experimentally, systemic inflammation induced by a bolus intravenous injection of lipopolysaccharide (LPS) may be accompanied by three different thermoregulatory responses: monophasic fever (the typical response to low doses of LPS), biphasic fever (medium doses), and hypothermia (high doses). In our recent study [Romanovsky, A. A., V. A. Kulchitsky, C. T. Simons, N. Sugimoto, and M. Szekely. Am. J. Physiol. (Regulatory Integrative Comp. Physiol.). In press], monophasic fever did not occur in subdiaphragmatically vagotomized rats. In the present work, we asked whether vagotomy affects the two other types of thermoregulatory response. Adult Wistar rats were vagotomized (or sham operated) and had an intravenous catheter implanted. On day 28 postvagotomy, the thermal responses to the intravenous injection of Escherichia coli LPS (0, 1, 10, 100, or 1,000 micrograms/kg) were tested in either a neutral (30 degrees C) or slightly cool (25 degrees C) environment. Three major results were obtained. 1) In the sham-operated rats, the 1 microgram/kg dose of LPS caused at 30 degrees C a monophasic fever with a maximal colonic temperature (Tc) rise of approximately 0.6 degree C; this response was abated (no Tc changes) in the vagotomized rats. 2) At 30 degrees C, all responses to higher doses of LPS (10-1,000 micrograms/kg) were represented by biphasic fevers (the higher the dose, the less pronounced the first and the more pronounced the second phase was); none of these biphasic fevers was altered in the vagotomized animals. 3) In response to the 1,000 micrograms/kg dose at 25 degrees C, hypothermia occurred: Tc changed by -0.5 +/- 0.1 degree C (nadir); this hypothermia was exaggerated (-1.1 +/- 0.1 degrees C) in the vagotomized rats. It is concluded that vagal afferentation may be important in the mediation of the response to minor amounts of circulating LPS, whereas the response to larger amounts is brought about mostly (if not exclusively) by nonvagal mechanisms. This difference may be explained by the dose-dependent mechanisms of the processing of exogenous pyrogens. Vagotomized animals also appear to be more sensitive to the hypothermizing action of LPS in a cool environment; the mechanisms of this phenomenon remain speculative.

scholarly journals Biphasic Dose–Response Induced by PCB150 and PCB180 in HeLa Cells and Potential Molecular Mechanisms

Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582091004
Author(s):  
Ainy Zehra ◽  
Muhammad Zaffar Hashmi ◽  
Abdul Majid Khan ◽  
Tariq Malik ◽  
Zaigham Abbas
Keyword(s):  
Hela Cells ◽  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Genotoxic Effects ◽  
Species Formation ◽  
Low Concentrations ◽  
Extracellular Signal ◽  
High Concentrations ◽  
High Doses ◽  
Dose Dependent

The polychlorinated biphenyls (PCBs) are persistent and their dose-dependent toxicities studies are not well-established. In this study, cytotoxic and genotoxic effects of PCB150 and PCB180 in HeLa cells were studied. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that the cell proliferation was stimulated at low doses (10−3 and 10−2 µg/mL for 12, 24, 48, and 72 hours) and inhibited at high doses (10 and 15 µg/mL for 24, 48, and 72 hours) for both PCBs. Increase in reactive oxygen species formation was observed in the HeLa cells in a time- and dose-dependent manner. Malondialdehyde and superoxide dismutase showed increased levels at high concentrations of PCBs over the time. Glutathione peroxidase expression was downregulated after PCBs exposure, suggested that both PCB congeners may attributable to cytotoxicity. Comet assay elicited a significant increase in genotoxicity at high concentrations of PCBs as compared to low concentrations indicating genotoxic effects. PCB150 and PCB180 showed decrease in the activity of extracellular signal–regulated kinase 1/2 and c-Jun N-terminal kinase at high concentrations after 12 and 48 hours. These findings may contribute to understanding the mechanism of PCBs-induced toxicity, thereby improving the risk assessment of toxic compounds in humans.

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