scholarly journals Partial Agonist Activity of Neonicotinoids on Rat Nicotinic Receptors: Consequences over Epinephrine Secretion and In Vivo Blood Pressure

2021 ◽  
Vol 22 (10) ◽  
pp. 5106
Author(s):  
Joohee Park ◽  
Antoine Taly ◽  
Jennifer Bourreau ◽  
Frédéric De Nardi ◽  
Claire Legendre ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Nicotinic Acetylcholine Receptors ◽  
Ex Vivo ◽  
Partial Agonist ◽  
Simultaneous Exposure ◽  
Vegetative Nervous System ◽  
Arterial Blood

Neonicotinoid insecticides are nicotine-derived molecules which exert acute neurotoxic effects over the insect central nervous system by activating nicotinic acetylcholine receptors (nAChRs). However, these receptors are also present in the mammalian central and peripheral nervous system, where the effects of neonicotinoids are faintly known. In mammals, cholinergic synapses are crucial for the control of vascular tone, blood pressure and skeletal muscle contraction. We therefore hypothesized that neonicotinoids could affect cholinergic networks in mammals and sought to highlight functional consequences of acute intoxication in rats with sub-lethal concentrations of the highly used acetamiprid (ACE) and clothianidin (CLO). In this view, we characterized their electrophysiological effects on rat α3β4 nAChRs, knowing that it is predominantly expressed in ganglia of the vegetative nervous system and the adrenal medulla, which initiates catecholamine secretion. Both molecules exhibited a weak agonist effect on α3β4 receptors. Accordingly, their influence on epinephrine secretion from rat adrenal glands was also weak at 100 M, but it was stronger at 500 M. Challenging ACE or CLO together with nicotine (NIC) ended up with paradoxical effects on secretion. In addition, we measured the rat arterial blood pressure (ABP) in vivo by arterial catheterization. As expected, NIC induced a significant increase in ABP. ACE and CLO did not affect the ABP in the same conditions. However, simultaneous exposure of rats to both NIC and ACE/CLO promoted an increase of ABP and induced a biphasic response. Modeling the interaction of ACE or CLO on α3β4 nAChR is consistent with a binding site located in the agonist pocket of the receptor. We present a transversal experimental approach of mammal intoxication with neonicotinoids at different scales, including in vitro, ex vivo, in vivo and in silico. It paves the way of the acute and chronic toxicity for this class of insecticides on mammalian organisms

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

Vasorelaxant and Antihypertensive Effects of Mentha pulegium L. in Rats: An in vitro and in vivo Approach

2020 ◽  
Vol 20 ◽  
Author(s):  
Mohammed Ajebli ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Acute Experiment ◽  
Antihypertensive Activity ◽  
Mentha Pulegium ◽  
In Vitro Experiment ◽  
Arterial Blood ◽  
Dose Dependent ◽  
Ca2 Channels

Aims and objective: The aim of the study was to investigate the effect of aqueous aerial part extract of Mentha pulegium L. (Pennyrile) (MPAE) on arterial pressure parameters in rats. Background: Mentha pulegium is a medicinal plant used to treat hypertension in Morocco. Material and methods: In the current study, MPAE was prepared and its antihypertensive activity was pharmacologically investigated. L-NAME-hypertensive and normotensive rats have received orally MPAE (180 and 300 mg/kg) during six hours for the acute experiment and during seven days for the sub-chronic treatment. Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. While, in the in vitro experiment, isolated denuded and intact thoracic aortic rings were suspended in a tissue bath system and the tension changes were recorded. Results: A fall in blood pressure was observed in L-NAME-induced hypertensive treated with MPAE. The extract also produced a dose-dependent relaxation of aorta pre-contracted with NE and KCl. The study showed that the vasorelaxant ability of MPAE seems to be exerted through the blockage of extracellular Ca2+ entry. Conclusion: The results demonstrate that the extract of pennyrile exhibits antihypertensive activity. In addition, the effect may be, at least in part, due to dilation of blood vessels via blockage of Ca2+ channels.

5-HT2B-receptor antagonist LY-272015 is antihypertensive in DOCA-salt-hypertensive rats

1999 ◽  
Vol 276 (3) ◽  
pp. H944-H952 ◽  
Author(s):  
Stephanie W. Watts ◽  
Gregory D. Fink
Keyword(s):  
Blood Pressure ◽  
Receptor Antagonist ◽  
High Blood Pressure ◽  
Reduce Blood Pressure ◽  
Receptor Expression ◽  
Hypertensive Rats ◽  
Arterial Blood ◽  
Salt Hypertension

We previously demonstrated a change in the receptors mediating 5-hydroxytryptamine (5-HT)-induced contraction in arteries of deoxycorticosterone acetate (DOCA)-salt-hypertensive rats. Specifically, contraction to 5-HT is mediated primarily by 5-HT2A receptors in arteries from normotensive sham rats and by both 5-HT2A and 5-HT2B receptors in arteries from hypertensive rats. We hypothesized that the 5-HT2B receptor may play a role in maintaining the high blood pressure of DOCA-salt-hypertensive rats, and herein we provide data connecting in vitro and in vivo findings. The endothelium-denuded isolated superior mesenteric artery of DOCA-salt rats displayed a marked increase in maximum contraction to the newly available 5-HT2B-receptor agonist BW-723C86 compared with that of arteries from sham rats, confirming that the 5-HT2B receptor plays a greater role in 5-HT-induced contraction in arteries from DOCA-salt rats. In chronically instrumented rats, the 5-HT2B-receptor antagonist LY-272015 (0.3, 1.0, and 3.0 mg/kg iv at 30-min intervals) was given cumulatively 1 time/wk during 4 wk of continued DOCA-salt treatment. LY-272015 did not reduce blood pressure of the sham-treated rats at any time or dose. However, LY-272015 (1.0 and 3.0 mg/kg) significantly reduced mean blood pressure in a subgroup of week 3 (−20 mmHg) and week 4 DOCA-salt (−40 mmHg) rats that had extremely high blood pressure (mean arterial blood pressure ∼200 mmHg). Blockade of 5-HT2Breceptors by in vivo administration of LY-272015 (3.0 mg/kg) was verified by observing reduced 5-HT-induced contraction in rat stomach fundus, the tissue from which the 5-HT2B receptor was originally cloned. These data support the novel hypothesis that 5-HT2B-receptor expression is induced during the development of DOCA-salt hypertension and contributes to the maintenance of severe blood pressure elevations.

In vitro and in vivo inhibition of renin by fatty acids.

1978 ◽  
Vol 234 (6) ◽  
pp. E593 ◽  
Author(s):  
T A Kotchen ◽  
W J Welch ◽  
R T Talwalkar
Keyword(s):  
Blood Pressure ◽  
Fatty Acids ◽  
Linoleic Acid ◽  
Angiotensin Ii ◽  
Neutral Lipids ◽  
Pressor Response ◽  
Arterial Blood ◽  
Arachidonic Acids

Circulating neutral lipids inhibit the in vitro renin reaction. To identify the inhibitor(s), free fatty acids were added to human renin and homologous substrate. Capric, lauric, palmitoleic, linoleic, and arachidonic acids each inhibited the rate of angiotensin I production in vitro (P less than 0.01). Inhibition by polysaturated fatty acids (linoleic and arachidonic) was less (P less than 0.01) after catalytic hydrogenation of the double bonds. To evaluate an in vivo effect of renin inhibition intra-arterial blood pressure responses to infusions of renin and angiotensin II (5.0 microgram) were measured in anephric rats (n = 6) before and after infusion of linoleic acid (10 mg iv). Mean increase of blood pressure to angiotensin II before (75 mmHg +/- 9) and after (90 +/- 12) linoleic acid did not differ (P greater than 0.05). However, the pressor response to renin after linoleic acid (18 +/- 3) was less (P less than 0.00)) than that before (102 +/- 13). In summary, several fatty acids inhibit the in vitro renin reaction, and in part inhibition is dependent on unsaturation. Linoleic acid also inhibits the in vivo pressor response to renin. These results suggest that fatty acids may modify the measurement of plasma renin activity and may also affect angiotensin production in vivo.

scholarly journals 3-Hydroxyphenylacetic Acid: A Blood Pressure-Reducing Flavonoid Metabolite

Nutrients ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Patrícia Dias ◽  
Jana Pourová ◽  
Marie Vopršalová ◽  
Iveta Nejmanová ◽  
Přemysl Mladěnka
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Ex Vivo ◽  
Laboratory Animals ◽  
Spontaneously Hypertensive ◽  
Porcine Coronary Artery ◽  
Arterial Blood ◽  
Hydroxyphenylacetic Acid ◽  
Dose Dependent Decrease

Regular intake of polyphenol-rich food has been associated with a wide variety of beneficial health effects, including the prevention of cardiovascular diseases. However, the parent flavonoids have mostly low bioavailability and, hence, their metabolites have been hypothesized to be bioactive. One of these metabolites, 3-hydroxyphenylacetic acid (3-HPAA), formed by the gut microbiota, was previously reported to exert vasorelaxant effects ex vivo. The aim of this study was to shed more light on this effect in vivo, and to elucidate the mechanism of action. 3-HPAA gave rise to a dose-dependent decrease in arterial blood pressure when administered i.v. both as a bolus and infusion to spontaneously hypertensive rats. In contrast, no significant changes in heart rate were observed. In ex vivo experiments, where porcine hearts from a slaughterhouse were used to decrease the need for laboratory animals, 3-HPAA relaxed precontracted porcine coronary artery segments via a mechanism partially dependent on endothelium integrity. This relaxation was significantly impaired after endothelial nitric oxide synthase inhibition. In contrast, the blockade of SKCa or IKCa channels, or muscarinic receptors, did not affect 3-HPAA relaxation. Similarly, no effects of 3-HPAA on cyclooxygenase nor L-type calcium channels were observed. Thus, 3-HPAA decreases blood pressure in vivo via vessel relaxation, and this mechanism might be based on the release of nitric oxide by the endothelial layer.

Suppressed basal antidiuretic hormone release during cyclooxygenase inhibition in conscious dogs

1983 ◽  
Vol 244 (4) ◽  
pp. R487-R491
Author(s):  
B. R. Walker
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Antidiuretic Hormone ◽  
Plasma Osmolality ◽  
Blood Gases ◽  
Conscious Dogs ◽  
Arterial Blood ◽  
The Central Nervous System

Both in vitro and in vivo experiments suggest that prostaglandins may affect antidiuretic hormone (ADH) release centrally. In addition, other studies show that prostaglandins administered peripherally may cause ADH release. However, these latter studies have been flawed by hemodynamic alterations and the use of anesthetics, which make interpretation difficult. The present study was designed to test for involvement of prostaglandins produced outside the central nervous system in ADH release in conscious dogs. Administration of meclofenamate (2 mg/kg and 2 mg X kg-1 X h 1, iv) resulted in a consistent fall in plasma ADH levels in five dogs. This diminution of ADH release occurred with no change in systemic hemodynamics, arterial blood gases, or plasma osmolality, suggesting that prostaglandins are important mediators of basal ADH release in the conscious dog. Because meclofenamate does not cross the blood-brain barrier, prostaglandins produced outside the central nervous system appear to be involved in this process. The specific prostaglandin involved or the site of action of prostaglandins on ADH release is not clear at this time.

PROSTACYCLIN (PGI2) FORMATION IN RELATION TO ANAPHYLATOXIN C5a GENERATION DURING RABBIT ENDOTOXIN SHOCK

1987 ◽  
Author(s):  
M Rampart ◽  
H Bult ◽  
A G Herman ◽  
P J Jose ◽  
T J Williams
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Endotoxin Shock ◽  
Rabbit Serum ◽  
Classical Pathway ◽  
E Coli ◽  
Arterial Blood ◽  
Anaphylatoxin C5a

Injection of endotoxin (LPS) in animals, a model for gram-negative septic shock, leads to intravascular activation of the complement system, and is one of the few conditions in which 6-oxo-PGF]CX and thromboxane (TX) B2 (non-enzymic metabolites of PGI2 and TXA2) can be detected in arterial blood. Previously we reported associations between complement activation, PGI2 biosynthesis and LPS-induced hypotension in rabbits. As C5a and C5adesArg trigger endothelial PGI2 formation in vitro, we have now measured the plasma levels of immunoreactive (ir) C5a in relation to generation of PGI2 and changes in arterial blood pressure in LPS shock. Pentobarbitone anaesthethized rabbits received LPS (E. coli 0111:B4, 0.5 mg/kg) or saline via the marginal ear vein. A catheter in the left carotid artery was used to collect blood and to monitor mean arterial blood pressure (MABP). Platelet and leukocyte numbers, haemolytic complement titre (CH50), and plasma ir6-oxo-PGFioc , irTXB2 and irC5a were measured 15 min before and at different times after saline or LPS injection. LPS caused a dose- and time-dependent formation of irC5a in rabbit serum in vitro, predominantly via the classical pathway. LPS also activated complement in vivo, as indicated by about 20 % reduction of CH50 titre (measured after 3h) and a marked increase of arterial irC5a (20-120 ng/ml) in the first 2 to 5 min. After 30 min, irC5a had returned to baseline levels (< 2-5 ng/ml) and remained so up to 3h after injection of LPS. This irC5a peak correlated with a shortlasting initiation of PGI2 release (from < 20 pg/ml up to 550 pg/ml) and a drop in MABP (from about 95 mmHg to 50 mmHg) 2-5 min after LPS. None of these changes occurred after saline injection.In conclusion, LPS activates complement in vivo with concomitant formation of C5a. This peptide may trigger -either directly or after phagocyte activation - endothelial PGI2 biosynthesis, leading to arterial hypotension. This is supported by the suppression of the initial rise of arterial ir6-oxo-PGF1α and hypotension in complement-depleted rabbits. Inhibition of C5a formation or activity may prove to be a meaningful approach to the treatment of septic circulatory shock.

Hypotensive effects of the triterpene oleanolic acid for cardiovascular prevention

2020 ◽  
Vol 13 ◽  
Author(s):  
A. Sureda ◽  
M. Monserrat-Mesquida ◽  
S. Pinya ◽  
P. Ferriol ◽  
S. Tejada
Keyword(s):  
Blood Pressure ◽  
Oleanolic Acid ◽  
Ex Vivo ◽  
Biological Activities ◽  
Cardiovascular Prevention ◽  
In Vivo Studies ◽  
Antihypertensive Activity ◽  
In Vitro Tests

Background:: Hypertension is a high prevalent chronic disease worldwide and a major cardiovascular risk factor. Oleanolic acid (3β-hydroxy-olea-12-en-28-oic acid) is a wide distributed bioactive pentacyclic triterpenoid with diverse biological activities such as anti-inflammatory, hepaprotective anti-diabetic or anti-hypertensive. Objective:: The aim of this study was to review and highlight the available data about antihypertensive activity of oleanolic acid and the described mechanisms of action. Method:: Extensive searches were made in the available literature on oleanolic acid and the data investigating its antihypertensive effects were analysed. Results:: Most of research has been performed on animal models of hypertension, ex vivo studies with aortic ring and some in vitro tests with cell cultures, whereas clinical trials are still lacking. Treatment of hypertensive animals with oleanolic acid significantly ameliorated the rise in the systolic blood pressure. In addition, the hypotensive effects of oleanolic acid are also related to a potent diuretic-natriuretic activity and nephroprotection. In vitro studies have characterized the participation of various signalling pathways that modulate the release of vasodilation mediators. Conclusion:: In vitro and in vivo studies suggest that oleanolic acid effectively reduce blood pressure and could be an interesting co-adjuvant to conventional treatment of hypertension.

IN VIVO SELECTIVITY BETWEEN HYPOTENSIVE AND PLATELET ANTIAGGREGATING ACTIONS OF ILOPROST AND PGI2 IN BEAGLE DOGS

1987 ◽  
Author(s):  
F Hermán ◽  
P Hadházy ◽  
K Magyar
Keyword(s):  
Blood Pressure ◽  
Platelet Aggregation ◽  
Arterial Blood Pressure ◽  
Bolus Administration ◽  
Beagle Dogs ◽  
Duration Of Action ◽  
Arterial Blood ◽  
Level Of Significance

Iloprost (Schering A.G.) is a chemically stable derivative of prostacyclin. We compared the hypotensive and antiaggregatory effects of PGI2 and Iloprost. The concentration producing 50% inhibition (IC50) of ADP-induced platelet aggregation in vitro was 0.35±0.15 nmol/1 for PGI2 and 0.56±0.2 nmol/1 for Iloprost (n=5). The in vivo antiaggregatory activity was measured with a modified filtration pressure technique (F.Hermán et al.Thromb. Res.44 /1986/, 575) in anaesthetized beagle dogs; the change in arterial blood pressure was recorded simultaneously. Using this technique, the dose-response relationship and the duration of action of prostacyclin and Iloprost following bolus administration have been determined. PGI2 was equipotent with Iloprost in inhibiting platelet aggregation in vivo (ED25: 0.25±0.04 nmol/kg; 0.28±0.05 respectively). At the same time PGI2 was two times as potent as Iloprost in decreasing the mean arterial blood pressure (ED25: 0.41±0.12 nmol/kg; 0.87±0.14 nmol/kg respectively). The antiaggregatory and hypotensive effects of Iloprost last longer in each experiment than that of PGI2, but did not reach the level of significance probably due to the considerable interindividual differences. The in vivo selectivity ratios (hypotensive potency/antiaggregatory potency) of Iloprost and PGI2 were 0.32 and 0.6 respectively. These results show that in anesthetized beagles Iloprost is somewhat more selective than PGI2 in inhibiting platelet aggregation.

Glomerular prostaglandin formation in two-kidney, one-clip hypertensive rats

1984 ◽  
Vol 247 (6) ◽  
pp. F975-F981 ◽  
Author(s):  
R. A. Stahl ◽  
U. Helmchen ◽  
M. Paravicini ◽  
L. J. Ritter ◽  
P. Schollmeyer
Keyword(s):  
Blood Pressure ◽  
Filtration Rate ◽  
In Vivo Studies ◽  
Cyclooxygenase Inhibitor ◽  
Severe Damage ◽  
Hypertensive Rats ◽  
Cyclooxygenase Inhibition ◽  
Arterial Blood

In vitro prostaglandin (PG) and thromboxane B2 (TXB2) formation by isolated glomeruli from normotensive (N) and two-kidney, one-clip hypertensive (2K,1C) rats was determined. When calculated on the basis of glomerular protein content, PGE2, 6-keto-PGF1 alpha and TXB2 production of glomeruli from clipped kidneys was significantly greater than PG and TXB2 formation of glomeruli from the untouched kidneys. When PG and TXB2 formation was calculated per amount of glomeruli, only PGE2 formation was found to be significantly greater in clipped kidneys. No severe damage of glomerular structure was found in the kidneys when studied by light microscopy. In additional in vivo studies, the effect of the cyclooxygenase inhibitor indomethacin on blood pressure and glomerular filtration rate (GFR) was evaluated. Following indomethacin GFR in 7 of 13 clipped kidneys of 2K,1C rats decreased from 363 +/- 77 to 188 +/- 51 microliter/100 g body wt, whereas six kidneys developed anuria. No effect of cyclooxygenase inhibition on GFR was found in N rats and in untouched kidneys of 2K,1C rats. Mean arterial blood pressure in 2K,1C hypertension fell significantly, from 158 +/- 10 to 135 +/- 7 mmHg, after cyclooxygenase inhibition. No effect was seen in N rats. The data suggest that increased glomerular PG formation in the clipped kidneys of 2K,1C rats is involved in the pathogenesis of hypertension in this animal model.

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