The real-time in vivo electrochemical measurement of nitric oxide and carbon monoxide release upon direct epidural electrical stimulation of the rat neocortex

The Analyst ◽  
2015 ◽  
Vol 140 (10) ◽  
pp. 3415-3421 ◽  
Author(s):  
Sarah S. Park ◽  
Minyoung Hong ◽  
Yejin Ha ◽  
Jeongeun Sim ◽  
Gil-Ja Jhon ◽  
...  

This study reports real-time,in vivofunctional measurement of nitric oxide (NO) and carbon monoxide (CO), two gaseous mediators in controlling vascular function.

2005 ◽  
Vol 289 (4) ◽  
pp. H1442-H1447 ◽  
Author(s):  
Charles W. Leffler ◽  
Liliya Balabanova ◽  
Alexander L. Fedinec ◽  
Helena Parfenova

Carbon monoxide (CO) and nitric oxide (NO) can be involved in the regulation of cerebral circulation. Inhibition of production of either one of these gaseous intercellular messengers inhibits newborn pig cerebral arteriolar dilation to the excitatory amino acid glutamate. Glutamate can increase NO production. Therefore, the present study tests the hypothesis that NO, which is increased by glutamate, stimulates the production of CO by cerebral microvessels. Experiments used freshly isolated cerebral microvessels from piglets that express only heme oxygenase-2 (HO-2). CO production was measured by gas chromatography-mass spectrometry. Although inhibition of nitric oxide synthase (NOS) with Nω-nitro-l-arginine (l-NNA) did not alter basal HO-2 catalytic activity or CO production, l-NNA blocked glutamate stimulation of HO-2 activity and CO production. Furthermore, the NO donor sodium nitroprusside mimicked the actions of glutamate on HO-2 and CO production. The action of NO appears to be via cGMP because 8-bromo-cGMP mimics and 1 H-[1,2,4]oxadiazole-[4,3- a]quinoxalin-1-one (ODQ) blocks glutamate stimulation of CO production and HO-2 catalytic activity. Inhibitors of neither casein kinase nor phosphotidylinositol 3-kinase altered HO-2 catalytic activity. Conversely, inhibition of calmodulin with calmidazolium chloride blocked glutamate stimulation of CO production and reduced HO-2 catalytic activity. These data suggest that glutamate may activate NOS producing NO that leads to CO synthesis via a cGMP-dependent elevation of HO-2 catalytic activity. These results are consistent with the findings in vivo that either HO or NOS inhibition blocks cerebrovascular dilation to glutamate in piglets.


2000 ◽  
Vol 83 (4) ◽  
pp. 1796-1808 ◽  
Author(s):  
Anthony R. West ◽  
Anthony A. Grace

A major component of the cortical regulation of the nigrostriatal dopamine (DA) system is known to occur via activation of striatal efferent systems projecting to the substantia nigra. The potential intermediary role of striatal nitric oxide synthase (NOS)-containing interneurons in modulating the efferent regulation of DA neuron activity was examined using single-unit recordings of DA neurons performed concurrently with striatal microdialysis in anesthetized rats. The response of DA neurons recorded in the substantia nigra to intrastriatal artificial cerebrospinal fluid (ACSF) or drug infusion was examined in terms of mean firing rate, percent of spikes fired in bursts, cells/track, and response to electrical stimulation of the orbital prefrontal cortex (oPFC) and striatum. Intrastriatal infusion of NOS substrate concurrently with intermittent periods of striatal and cortical stimulation increased the mean DA cell population firing rate as compared with ACSF controls. This effect was reproduced via intrastriatal infusion of a NO generator. Infusion of either a NOS inhibitor or NO chelator via reverse microdialysis did not affect basal firing rate but increased the percentage of DA neurons responding to striatal stimulation with an initial inhibition followed by a rebound excitation (IE response) from 40 to 74%. NO scavenger infusion also markedly decreased the stimulation intensity required to elicit an IE response to electrical stimulation of the striatum. In single neurons in which the effects of electrical stimulation were observed before and after drug delivery, NO antagonist infusion was observed to decrease the onset latency and extend the duration of the initial inhibitory phase induced by either oPFC or striatal stimulation. This is the first report showing that striatal NO tone regulates the basal activity and responsiveness of DA neurons to cortical and striatal inputs. These studies also indicate that striatal NO signaling may play an important role in the integration of information transmitted to basal ganglia output centers via corticostriatal and striatal efferent pathways.


Author(s):  
Theresa Chikopela ◽  
Douglas C. Heimburger ◽  
Longa Kaluba ◽  
Pharaoh Hamambulu ◽  
Newton Simfukwe ◽  
...  

Abstract Background Endothelial function is dependent on the balance between vasoconstrictive and vasodilatory substances. The endothelium ability to produce nitric oxide is one of the most crucial mechanisms in regulating vascular tone. An increase in inducible nitric oxide synthase contributes to endothelial dysfunction in overweight persons, while oxidative stress contributes to the conversion of nitric oxide to peroxynitrite (measured as nitrotyrosine in vivo) in underweight persons. The objective of this study was to elucidate the interaction of body composition and oxidative stress on vascular function and peroxynitrite. This was done through an experimental design with three weight groups (underweight, normal weight and overweight), with four treatment arms in each. Plasma nitrotyrosine levels were measured 15–20 h post lipopolysaccharide (LPS) treatment, as were aortic ring tension changes. Acetylcholine (ACh) and sodium nitroprusside (SNP) challenges were used to observe endothelial-dependent and endothelial-independent vascular relaxation after pre-constriction of aortic rings with phenylephrine. Results Nitrotyrosine levels in saline-treated rats were similar among the weight groups. There was a significant increase in nitrotyrosine levels between saline-treated rats and those treated with the highest lipopolysaccharide doses in each of the weight groups. In response to ACh challenge, Rmax (percentage reduction in aortic tension) was lowest in overweight rats (112%). In response to SNP, there was an insignificantly lower Rmax in the underweight rats (106%) compared to the normal weight rats (112%). Overweight rats had a significant decrease in Rmax (83%) in response to SNP, signifying involvement of a more chronic process in tension reduction changes. A lower Rmax accompanied an increase in peroxynitrite after acetylcholine challenge in all weight groups. Conclusions Endothelial dysfunction, observed as an impairment in the ability to reduce tension, is associated with increased plasma peroxynitrite levels across the spectrum of body mass. In higher-BMI rats, an additional role is played by vascular smooth muscle in the causation of endothelial dysfunction.


1999 ◽  
Vol 46 (4) ◽  
pp. 461-469 ◽  
Author(s):  
C.Q. Huang ◽  
R.K. Shepherd ◽  
P.M. Center ◽  
P.M. Seligman ◽  
B. Tabor

1999 ◽  
Vol 6 (1) ◽  
pp. 63-76 ◽  
Author(s):  
Min Zhuo ◽  
Jarmo T. Laitinen ◽  
Xiao-Ching Li ◽  
Robert D. Hawkins

Perfusion of hippocampal slices with an inhibitor nitric oxide (NO) synthase blocked induction of long-term potentiation (LTP) produced by a one-train tetanus and significantly reduced LTP by a two-train tetanus, but only slightly reduced LTP by a four-train tetanus. Inhibitors of heme oxygenase, the synthetic enzyme for carbon monoxide (CO), significantly reduced LTP by either a two-train or four-train tetanus. These results suggest that NO and CO are both involved in LTP but may play somewhat different roles. One possibility is that NO serves a phasic, signaling role, whereas CO provides tonic, background stimulation. Another possibility is that NO and CO are phasically activated under somewhat different circumstances, perhaps involving different receptors and second messengers. Because NO is known to be activated by stimulation of NMDA receptors during tetanus, we investigated the possibility that CO might be activated by stimulation of metabotropic glutamate receptors (mGluRs). Consistent with this idea, long-lasting potentiation by the mGluR agonist tACPD was blocked by inhibitors of heme oxygenase but not NO synthase. Potentiation by tACPD was also blocked by inhibitors of soluble guanylyl cyclase (a target of both NO and CO) or cGMP-dependent protein kinase, and guanylyl cyclase was activated by tACPD in hippocampal slices. However, biochemical assays indicate that whereas heme oxygenase is constitutively active in hippocampus, it does not appear to be stimulated by either tetanus or tACPD. These results are most consistent with the possibility that constitutive (tonic) rather than stimulated (phasic) heme oxygenase activity is necessary for potentiation by tetanus or tACPD, and suggest that mGluR activation stimulates guanylyl cyclase phasically through some other pathway.


2005 ◽  
Vol 289 (2) ◽  
pp. H916-H923 ◽  
Author(s):  
Nelson N. Orie ◽  
Patrick Vallance ◽  
Dean P. Jones ◽  
Kevin P. Moore

It is now established that S-nitroso-albumin (SNO-albumin) circulates at low nanomolar concentrations under physiological conditions, but concentrations may increase to micromolar levels during disease states (e.g., cirrhosis or endotoxemia). This study tested the hypothesis that high concentrations of SNO-albumin observed in some diseases modulate vascular function and that it acts as a stable reservoir of nitric oxide (NO), releasing this molecule when the concentrations of low-molecular-weight thiols are increased. SNO-albumin was infused into rats to increase the plasma concentration from <50 nmol/l to ∼4 μmol/l. This caused a 29 ± 6% drop in blood pressure, 20 ± 4% decrease in aortic blood flow, and a 25 ± 14% reduction of renal blood flow within 10 min. These observations were in striking contrast to those of an infused arterial vasodilator (hydralazine), which increased aortic blood flow, and suggested that SNO-albumin acts primarily as a venodilator in vivo. This was confirmed by the observations that glyceryl trinitrate (a venodilator) led to similar hemodynamic changes and that the hemodynamic effects of SNO-albumin are reversed by infusion of colloid. Infusion of N-acetylcysteine into animals with artificially elevated plasma SNO-albumin concentrations led to the rapid decomposition of SNO-albumin in vivo and reproduced the hemodynamic effects of SNO-albumin infusion. These data demonstrate that SNO-albumin acts primarily as a venodilator in vivo and represents a stable reservoir of NO that can release NO when the concentrations of low-molecular-weight thiols are elevated.


1983 ◽  
Vol 244 (4) ◽  
pp. E317-E322 ◽  
Author(s):  
F. Rohner-Jeanrenaud ◽  
A. C. Hochstrasser ◽  
B. Jeanrenaud

In vivo glucose-induced insulin secretion was greater in preweaned preobese 17-day-old Zucker rats than in the corresponding controls. This hypersecretion of insulin was reversed to normal by acute pretreatment with atropine. A short-lived (30 s) electrical stimulation of the vagus nerve preceding a glucose load potentiated the in vivo glucose-induced insulin release in adult animals (6-9 wk) and more so in obese Zucker (fa/fa) than in lean rats. This suggested the existence of enhanced sensitivity and/or responsiveness of the B cells of obese animals to the parasympathetic system. That the parasympathetic tone was increased in adult obese Zucker (fa/fa) rats was corroborated by the observation that acute vagotomy of these animals resulted in a significant decrease in glucose-induced insulin secretion, whereas no such effect was seen in lean rats. Also, perfused pancreases from adult obese (fa/fa) rats oversecreted insulin during a stimulation by arginine when compared with controls, an oversecretion that was restored toward normal by superimposed infusion of atropine. It is concluded that a) the increased insulin secretion of preobese Zucker fa/fa rats is an early abnormality that is mediated by the vagus nerve, and b) increased secretion of insulin in adult obese fa/fa rats continues to be partly vagus-nerve mediated, although a decreased sympathetic tone and other unknown defects could conceivably play a role as well.


2019 ◽  
Author(s):  
Sebastiano Bariselli ◽  
Nanami Miyazaki ◽  
Alexxai Kravitz

AbstractStimulants are one of the most widely prescribed classes of pharmaceuticals, but it is unclear which brain pathways underlie their therapeutic and adverse actions. Here, with real-time monitoring of circuit plasticity, we demonstrate that psychostimulants strengthen orbitofrontal (OFC) to dorsomedial striatum (DMS) pathway synapses, and increase striatal output in awake mice. In vivo high-frequency stimulation of OFC-DMS pathway blocked stimulant-induced potentiation and the expression of locomotor sensitization, thereby directly linking OFC-DMS plasticity to hyperactivity.


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