scholarly journals Induction of capacitation and the acrosome reaction of boar spermatozoa by L-arginine and nitric oxide synthesis associated with the anion transport system

Reproduction ◽  
2002 ◽  
pp. 857-864 ◽  
Author(s):  
H Funahashi
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Acrosome Reaction ◽  
Fluorescein Isothiocyanate ◽  
Anion Transport ◽  
Nitric Oxide Synthesis ◽  
The Status ◽  
Anion Transport System ◽  
Synthase Inhibitor ◽  
Boar Spermatozoa

The aim of this study was to determine the effect of L-arginine on nitric oxide (NO) synthesis, capacitation and acrosome reaction of boar spermatozoa. Ejaculated boar spermatozoa were washed and then cultured in a bicarbonate:CO(2)-buffered medium, modified NCSU-37, for 2 h. At the end of the culture, the status of spermatozoa was determined. The presence of (0.1-2.0 mmol l(-1)) L-arginine in the culture medium induced an acrosome reaction as determined by fluorescein isothiocyanate-peanut agglutinin (FITC-PNA) and increased intracellular NO content, as quantified by a fluorescent indicator, diaminofluorescein-2 diacetate (DAF-2 DA). This stimulatory effect of L-arginine was neutralized by supplementation with an NO synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (1 mmol l(-1)). However, the inactive enantiomorph, N(omega)-nitro-D-arginine methyl ester, did not affect the stimulatory effect of L-arginine. These results indicate that L-arginine induces an acrosome reaction through the NO signal pathway in boar spermatozoa. Furthermore, the stimulatory effect of L-arginine was inhibited in the presence of an anion transport inhibitor, 4-acetamido-4'-isothiocyano-stilbene-2,2'-disulphonic acid (SITS; 0.1 mmol l(-1)), whereas any responses of spermatozoa to caffeine were not inhibited by SITS. A stimulatory effect of L-arginine on capacitation and acrosome reaction of spermatozoa was also observed in modified NCSU37 medium by using a chlortetracycline fluorescence assay, but not in supplemented bicarbonate-free Tris-buffered medium. These results indicate that the presence of L-arginine induces nitric oxide synthesis and stimulates capacitation and acrosome reaction of boar spermatozoa only when active sperm anion transport is present as a result of bicarbonate supplementation.

Nitric oxide and cerebral blood flow responses to hyperbaric oxygen

2000 ◽  
Vol 88 (4) ◽  
pp. 1381-1389 ◽  
Author(s):  
Ivan T. Demchenko ◽  
Albert E. Boso ◽  
Thomas J. O'Neill ◽  
Peter B. Bennett ◽  
Claude A. Piantadosi
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Methyl Ester ◽  
No Production ◽  
No Donors ◽  
Mk 801 ◽  
Neuronal Excitation ◽  
Synthase Inhibitor ◽  
Electroencephalogram Eeg

We have tested the hypothesis that cerebral nitric oxide (NO) production is involved in hyperbaric O2 (HBO2) neurotoxicity. Regional cerebral blood flow (rCBF) and electroencephalogram (EEG) were measured in anesthetized rats during O2 exposure to 1, 3, 4, and 5 ATA with or without administration of the NO synthase inhibitor ( N ω-nitro-l-arginine methyl ester), l-arginine, NO donors, or the N-methyl-d-aspartate receptor inhibitor MK-801. After 30 min of O2 exposure at 3 and 4 ATA, rCBF decreased by 26–39% and by 37–43%, respectively, and was sustained for 75 min. At 5 ATA, rCBF decreased over 30 min in the substantia nigra by one-third but, thereafter, gradually returned to preexposure levels, preceding the onset of EEG spiking activity. Rats pretreated with N ω-nitro-l-arginine methyl ester and exposed to HBO2 at 5 ATA maintained a low rCBF. MK-801 did not alter the cerebrovascular responses to HBO2at 5 ATA but prevented the EEG spikes. NO donors increased rCBF in control rats but were ineffective during HBO2 exposures. The data provide evidence that relative lack of NO activity contributes to decreased rCBF under HBO2, but, as exposure time is prolonged, NO production increases and augments rCBF in anticipation of neuronal excitation.

The Nitric Oxide Synthase Inhibitor NG-nitro-L-Arginine Methyl Ester Potentiates Insulin Secretion Stimulated by Glucose and L-Arginine Independently of its Action on ATP-Sensitive K+ Channels

1998 ◽  
Vol 18 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Albert Salehi ◽  
Fariborz Parandeh ◽  
Ingmar Lundquist
Keyword(s):  
Nitric Oxide ◽  
Insulin Secretion ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
Insulin Release ◽  
Glucagon Secretion ◽  
Nitric Oxide Synthase Inhibitor ◽  
Insulin And Glucagon Secretion ◽  
Synthase Inhibitor ◽  
Oxide Synthase

The nature of the action of the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on hormone release from isolated islets was investigated. We found that glucose-induced insulin release was potentiated by L-NAME in the absence or presence of diazoxide, a potent K+ATP channel opener, as well as in the presence of diazoxide plus a depolarizing concentration of K+. At a low, physiological glucose concentration L-NAME did not influence insulin secretion induced by K+ but inhibited glucagon secretion. L-arginine-induced insulin release was potentiated by L-NAME. This potentiation was observed also in the presence of K+ plus diazoxide. Further, glucagon release induced by L-arginine as well as by L-arginine plus K+ and diazoxide was suppressed by L-NAME. The results strongly suggest that the L-NAME-induced potentiation of insulin secretion in response to glucose or L-arginine as well as the inhibitory effects on glucagon secretion are largely mediated by L-NAME directly suppressing islet NOS activity. Hence NO apparently affects insulin and glucagon secretion independently of membrane depolarization events.

Nitric Oxide is a Mediator of the Late-Phase Response in an Animal Model of Nasal Allergy

2000 ◽  
Vol 122 (5) ◽  
pp. 706-711 ◽  
Author(s):  
William F. Durland ◽  
Andrew P. Lane ◽  
Kimberly W. Durland ◽  
Timothy L. Smith ◽  
Kenneth L. Johnson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Inflammatory Cell ◽  
Late Phase ◽  
Phase Response ◽  
Brown Norway ◽  
Nasal Allergy ◽  
Synthase Inhibitor ◽  
Histamine Challenge

The presence of nitric oxide (NO) in the nose is well documented; however, the role of this molecule in nasal physiology is still poorly understood. Our laboratory has previously demonstrated that NO is a mediator of the immediate secretory response to an intranasal histamine challenge in a rat model of nasal allergy. Histamine challenge, however, does not elicit a late-phase response (LPR). To study the role of NO in the LPR, we developed a model of nasal allergy in which brown Norway rats are actively sensitized to the allergen ovalbumin and later challenged intranasally with either phosphate-buffered saline solution (vehicle), ovalbumin in vehicle, or ovalbumin and the NO synthase inhibitor N-nitro-L-arginine methyl ester. In each experiment, nasal lavage samples were collected 30, 120, 240, and 360 minutes after challenge. Lavage samples were analyzed for albumin content by ELISA, inflammatory cell concentration with a hemocytometer, and evidence of inflammation by light microscopy. Blocking NO synthesis with N-nitro-L-arginine methyl ester significantly inhibited both albumin exudation and inflammatory cell influx into the nasal cavity during the LPR. These data suggest that NO plays a role in the LPR of nasal allergy.

Adverse effects of pneumoperitoneum on renal function: involvement of the endothelin and nitric oxide systems

2008 ◽  
Vol 294 (3) ◽  
pp. R842-R850 ◽  
Author(s):  
Zaid Abassi ◽  
Bishara Bishara ◽  
Tony Karram ◽  
Samer Khatib ◽  
Joseph Winaver ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Adverse Effects ◽  
Renal Dysfunction ◽  
Kidney Function ◽  
Renal Plasma Flow ◽  
Abdominal Pressure ◽  
Oxide Systems ◽  
Excretory Function ◽  
Synthase Inhibitor

Increased intra-abdominal pressure (IAP) during laparoscopy adversely affects kidney function. The mechanism underlying this phenomenon is largely unknown. This study was designed to investigate the involvement of endothelin (ET)-1 and nitric oxide (NO) systems in IAP-induced renal dysfunction. Rats were subjected to IAP of 14 mmHg for 1 h, followed by a deflation for 60 min (recovery). Four additional groups were pretreated with 1) ABT-627, an ETA antagonist; 2) A-192621, an ETB antagonist; 3) nitroglycerine; and 4) NG-nitro-l-arginine methyl ester, a NO synthase inhibitor, before IAP. Urine flow rate (V), absolute Na+ excretion (UNaV), glomerular filtration rate (GFR), and renal plasma flow (RPF) were determined. Significant reductions in kidney function and hemodynamics were observed when IAP was applied. V decreased from 8.1 ± 1.0 to 5.8 ± 0.5 μl/min, UNaV from 1.08 ± 0.31 to 0.43 ± 0.10 μeq/min, GFR from 1.84 ± 0.12 to 1.05 ± 0.06 ml/min (−46.9 ± 2.7% from baseline), and RPF from 8.62 ± 0.87 to 3.82 ± 0.16 ml/min (−54 ± 3.5% from baseline). When the animals were pretreated with either ABT-627 or A-192621, given alone or combined, the adverse effects of IAP on GFR, RPF, V, and UNaV were significantly augmented. When the animals were pretreated with nitroglycerine, the adverse effects of pneumoperitoneum on GFR and RPF were substantially improved. In contrast, pretreatment with NG-nitro-l-arginine methyl ester remarkably aggravated pneumoperitoneum-induced renal dysfunction. In conclusion, decreased renal excretory function and hypofiltration are induced by increased IAP. These effects are related to impairment of renal hemodynamics and could be partially ameliorated by pretreatment with nitroglycerine and aggravated by NO and ET blockade.

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