scholarly journals Possible Origins and Distribution of Immunoreactive Nitric Oxide Synthase-Containing Nerve Fibers in Cerebral Arteries

1993 ◽  
Vol 13 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Kazuhiko Nozaki ◽  
Michael A. Moskowitz ◽  
Kenneth I. Maynard ◽  
Naoki Koketsu ◽  
Ted M. Dawson ◽  
...  

The distribution of perivascular nerve fibers expressing nitric oxide synthase (NOS)-immunoreactivity was examined in Sprague–Dawley and Long–Evans rats using affinity-purified rabbit antisera raised against NOS from rat cerebellum. NOS immunoreactivity was expressed within the endothelium and adventitial nerve fibers in both rat strains. Labeled axons were abundant and dense in the proximal anterior and middle cerebral arteries, but were less numerous in the caudal circle of Willis and in small pial arteries. The sphenopalatine ganglia were the major source of positive fibers in these vessels. Sectioning postganglionic parasympathetic fibers from both sphenopalatine ganglia reduced the density of NOS-immunoreactive (IR) nerve fibers by >75% in the rostral circle of Willis. Moreover, NOS-IR was present in 70–80% of sphenopalatine ganglion cells. Twenty percent of these neurons also contained vasoactive intestinal polypeptide (VlP)-immunoreactivity. By contrast, the superior cervical ganglia did not contain NOS-IR cells. In the trigeminal ganglion, NO-IR neurons were found chiefly within the ophthalmic division; ∼10–15% of neurons were positively labeled. Colocalization with calcitonin gene-related peptide (CGRP) was not observed. Sectioning the major trigeminal branch innervating the circle of Willis decreased positive fibers by ≤25% in the ipsilateral vessels. In the nodose ganglion, 20–30% of neurons contained NOS-immunoreactivity, whereas less than 1% were in the C2 and C3 dorsal root ganglia. Three human circles of Willis obtained at autopsy showed sparse immunoreactive fibers, chiefly within vessels of the posterior circulation. Postmortem delay accounted for some of the reduced density. Our findings indicate that nerve fibers innervating cerebral arteries may serve as a nonendothelial source of the vasodilator nitric oxide (NO). The coexistence of NOS and VIP within sphenopalatine ganglion cells raises the possibility that two vasodilatory agents, one, a highly diffusable short-lived, low-molecular-weight molecule, and the other, a polar 28 amino acid-containing peptide, may serve as coneuromediators within the cerebral circulation.

1996 ◽  
Vol 84 (4) ◽  
pp. 648-654 ◽  
Author(s):  
Ryszard M. Pluta ◽  
B. Gregory Thompson ◽  
Ted M. Dawson ◽  
Solomon H. Snyder ◽  
Robert J. Boock ◽  
...  

✓ To determine the distribution of nitric oxide synthase (NOS) in the primate cerebral artery nervi vasorum and to examine the potential role of NOS in cerebral vasospasm after subarachnoid hemorrhage (SAH) in primates, the distribution of NOS immunoreactivity (NOS-IR) in the major cerebral arteries was examined immunohistochemically in cynomolgus monkeys by the use of whole, mounted preparations of the circle of Willis. In four normal monkeys, NOS-IR was localized to the endothelial and adventitial layers of the large cerebral arteries. On the abluminal side, NOS-IR staining was densely concentrated in perivascular nerve fibers (nervi vasorum) of the anterior circulation. Staining was less prominent in the posterior circulation. In six monkeys with vasospasm on Day 7 after placement of preclotted arterial blood to form an SAH around the right middle cerebral artery (MCA) (42% ± 8.3% decrease of MCA area, mean ± standard deviation), NOS-IR was virtually absent in nerve fibers around the spastic right MCA but was normal on the contralateral side. In five monkeys in which vasospasm resolved by Day 14 after SAH (36% ± 14% decrease of right MCA area on Day 7, and 5% ± 14% decrease on Day 14), NOS-IR was also absent in the right MCA adventitial nerve fibers and remained normal in the left MCA. Adventitial NOS-IR was also normal in cerebral vessels of a sham-operated, nonspastic monkey. These findings provide further evidence that nitric oxide (NO) functions as a neuronal transmitter to mediate vasodilation in primates and indicate a role for adventitial NO in the pathogenesis of cerebral vasospasm after SAH in humans.


1997 ◽  
Vol 17 (9) ◽  
pp. 977-984 ◽  
Author(s):  
Carmen González ◽  
Carla Barroso ◽  
Carmen Martín ◽  
Sergio Gulbenkian ◽  
Carmen Estrada

The participation of nitric oxide and vasoactive intestinal peptide (VIP) in the neurogenic regulation of bovine cerebral arteries was investigated. Nitrergic nerve fibers and ganglion-like groups of neurons were revealed by NADPH-diaphorase staining in the adventitial layer of bovine cerebral arteries. NADPH diaphorase also was present in endothelial cells but not in the smooth muscle layer. Double immunolabeling for neuronal nitric oxide synthase and VIP indicated that both molecules co-localized in the same nerve fibers in these vessels. Transmural nerve stimulation (200 mA, 0.2 milliseconds, 1 to 8 Hz) of endothelium-denuded bovine cerebral artery rings precontracted with prostaglandin F2α, produced tetrodotoxin-sensitive relaxations that were completely suppressed by NG-nitro-l-arginine methyl ester (l-NAME) and by the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline (ODQ), but were not affected by the adenylyl cyclase inhibitor 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ 22,536), nor by VIP tachyphylaxis induced by pretreatment with 1 μmol/L VIP. Transmural nerve stimulation also elicited increases in intracellular cyclic GMP concentration, which were prevented by l-NAME, and small decreases in intracellular cyclic AMP concentration. Addition of VIP to bovine cerebral artery rings without endothelium produced a concentration-dependent relaxation that was partially inhibited by l-NAME, ODQ, and SQ 22,536. The effects of l-NAME and SQ 22,536 were additive. VIP induced a transient increase in intracellular cyclic GMP concentration, which was maximal 1 minute after VIP addition, when the highest relaxation rate was observed, and which was blocked by l-NAME. It is concluded that nitric oxide produced by perivascular neurons and nerve fibers fully accounts for the experimental neurogenic relaxation of bovine cerebral arteries and that VIP, which also is present in the same perivascular fibers, acts as a neuromodulator by activating neuronal nitric oxide synthase.


1997 ◽  
Vol 273 (2) ◽  
pp. H718-H724 ◽  
Author(s):  
H. Kinoshita ◽  
S. Milstien ◽  
C. Wambi ◽  
Z. S. Katusic

Tetrahydrobiopterin is an essential cofactor in biosynthesis of nitric oxide. The present study was designed to determine the effect of decreased intracellular tetrahydrobiopterin levels on endothelial function of isolated cerebral arteries. Blood vessels were incubated for 6 h in minimum essential medium (MEM) in the presence or absence of a GTP cyclohydrolase I inhibitor, 2,4-diamino-6-hydroxypyrimidine (DAHP, 10(-2) M). Rings with and without endothelium were suspended for isometric force recording in the presence of a cyclooxygenase inhibitor, indomethacin (10(-5) M). In arteries with endothelium, DAHP significantly reduced intracellular levels of tetrahydrobiopterin. DAHP in combination with a precursor of the salvage pathway of tetrahydrobiopterin biosynthesis, sepiapterin (10(-4) M), not only restored but increased levels of tetrahydrobiopterin above control values. In DAHP-treated arteries, endothelium-dependent relaxations to bradykinin (10(-10)-10(-6) M) or calcium ionophore A23187 (10(-9)-10(-6) M) were significantly reduced, whereas endothelium-independent relaxations to a nitric oxide donor, 3-morpholinosydnonimine (10(-9)-10(-4) M), were not affected. When DAHP-treated arteries with endothelium were incubated with sepiapterin (10(-4) M) or superoxide dismutase (150 U/ml), relaxations to bradykinin and A23187 were restored to control levels. In contrast, superoxide dismutase did not affect endothelium-dependent relaxations in arteries incubated in MEM. A nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (10(-4) M), abolished relaxations to bradykinin or A23187 in control arteries and in DAHP-treated arteries. These studies demonstrate that in cerebral arteries, decreased intracellular levels of tetrahydrobiopterin can reduce endothelium-dependent relaxations. Production of superoxide anions during activation of dysfunctional endothelial nitric oxide synthase appears to be responsible for the impairment of endothelial function.


1993 ◽  
Vol 606 (1) ◽  
pp. 148-155 ◽  
Author(s):  
Costantino Iadecola ◽  
Alvin J. Beitz ◽  
Waleed Renno ◽  
Xiaohong Xu ◽  
Bernd Mayer ◽  
...  

2006 ◽  
Vol 101 (1) ◽  
pp. 348-353 ◽  
Author(s):  
Rhonda D. Prisby ◽  
M. Keith Wilkerson ◽  
Elke M. Sokoya ◽  
Robert M. Bryan ◽  
Emily Wilson ◽  
...  

Cephalic elevations in arterial pressure associated with microgravity and prolonged bed rest alter cerebrovascular autoregulation in humans. Using the head-down tail-suspended (HDT) rat to chronically induce headward fluid shifts and elevate cerebral artery pressure, previous work has likewise shown cerebral perfusion to be diminished. The purpose of this study was to test the hypothesis that 2 wk of HDT reduces cerebral artery vasodilation. To test this hypothesis, dose-response relations for endothelium-dependent (2-methylthioadenosine triphosphate and bradykinin) and endothelium-independent (nitroprusside) vasodilation were determined in vitro in middle cerebral arteries (MCAs) from HDT and control rats. All in vitro measurements were done in the presence and absence of the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester (10−5 M) and cyclooxygenase inhibitor indomethacin (10−5 M). MCA caveolin-1 protein content was measured by immunoblot analysis. Endothelium-dependent vasodilation to 2-methylthioadenosine triphosphate and bradykinin were both lower in MCAs from HDT rats. These lower vasodilator responses were abolished with NG-nitro-l-arginine methyl ester but were unaffected by indomethacin. In addition, HDT was associated with lower levels of MCA caveolin-1 protein. Endothelium-independent vasodilation was not altered by HDT. These results indicate that chronic cephalic fluid shifts diminish endothelium-dependent vasodilation through alterations in the endothelial nitric oxide synthase signaling mechanism. Such decrements in endothelium-dependent vasodilation of cerebral arteries could contribute to the elevations in cerebral vascular resistance and reductions in cerebral perfusion that occur after conditions of simulated microgravity in HDT rats.


1998 ◽  
Vol 274 (3) ◽  
pp. F516-F524 ◽  
Author(s):  
Atsuhiro Ichihara ◽  
Edward W. Inscho ◽  
John D. Imig ◽  
L. Gabriel Navar

This study was performed to determine the influence of neuronal nitric oxide synthase (nNOS) on renal arteriolar tone under conditions of normal, interrupted, and increased volume delivery to the macula densa segment and on the microvascular responses to angiotensin II (ANG II). Experiments were performed in vitro on afferent (21.2 ± 0.2 μm) and efferent (18.5 ± 0.2 μm) arterioles of kidneys harvested from male Sprague-Dawley rats, using the blood-perfused juxtamedullary nephron technique. Superfusion with the specific nNOS inhibitor, S-methyl-l-thiocitrulline (l-SMTC), decreased afferent and efferent arteriolar diameters, and these decreases in arteriolar diameters were prevented by interruption of distal volume delivery by papillectomy. When 10 mM acetazolamide was added to the blood perfusate to increase volume delivery to the macula densa segment, afferent arteriolar vasoconstrictor responses tol-SMTC were enhanced, but this effect was again completely prevented after papillectomy. In contrast, the arteriolar diameter responses to the nonselective NOS inhibitor, N ω-nitro-l-arginine (l-NNA) were only attenuated by papillectomy.l-SMTC (10 μM) enhanced the efferent arteriolar vasoconstrictor response to ANG II but did not alter the afferent arteriolar vasoconstrictor responsiveness to ANG II. In contrast, l-NNA (100 μM) enhanced both afferent and efferent arteriolar vasoconstrictor responses to ANG II. These results indicate that the modulating influence of nNOS on afferent arteriolar tone of juxtamedullary nephrons is dependent on distal tubular fluid flow. Furthermore, nNOS exerts a differential modulatory action on the juxtamedullary microvasculature by enhancing efferent, but not afferent, arteriolar responsiveness to ANG II.


2020 ◽  
Vol 319 (2) ◽  
pp. F192-F201
Author(s):  
Lindsey A. Ramirez ◽  
Ellen E. Gillis ◽  
Jacqueline B. Musall ◽  
Riyaz Mohamed ◽  
Elizabeth Snyder ◽  
...  

We have previously shown that hypertensive female rats have more regulatory T cells (Tregs), which contribute more to blood pressure (BP) control in female versus male rats. Based on known protective properties of Tregs, the goal of the present study was to investigate the mechanisms by which female rats maintain Tregs. The present study was designed to 1) compare the impact of three hypertension models on the percentage of renal Tregs and 2) test the hypothesis that nitric oxide synthase (NOS) inhibition prevents increases in renal Tregs and exacerbates renal damage in female Sprague-Dawley rats. Rats (11–14 wk old) were randomized to one of the following four groups: control, norepinephrine (NE) infusion, angiotensin II infusion, or the NOS inhibitor Nω-nitro-l-arginine methyl ester (l-NAME) in drinking water. BP was measured via tail cuff. After 2 wk of treatment, kidneys were isolated and processed to measure Tregs via flow cytometric analysis and renal injury via urinary albumin excretion, plasma creatinine, and histological analyses. Hypertensive treatments increased BP in all experimental animals. Increases in BP in norepinephrine-and angiotensin II-treated rats were associated with increases in renal Tregs versus control. In contrast, l-NAME treatment decreased Tregs compared with all groups. l-NAME treatment modestly increased albumin excretion. However, plasma creatinine was comparable among the groups, and there was no histological evidence of glomerular or tubular injury. This study provides insights into the mechanisms regulating renal Tregs and supports that an intact NOS system is crucial for female rats to have BP-related increases in renal Tregs.


1994 ◽  
Vol 111 (4) ◽  
pp. 430-438 ◽  
Author(s):  
Andrew Harper ◽  
William R. Blythe ◽  
Carlton J. Zdanski ◽  
Jiri Prazma ◽  
Harold C. Pillsbury

Nitric oxide is known to function as a neurotransmitter in the central nervous system. It is also known to be involved in the control nervous system excitatory amino acid neurotransmission cascade. Activation of excitatory amino acid receptors causes an influx of calcium, which activates nitric oxide synthase. The resulting increase in intracellular nitric oxide activates soluble guanylate cyclase, leading to a rise in cyclic guanosine monophosphate. The excitatory amino acids giutamate and aspartate are found in the vestibular system and have been postulated to function as vestibular system neurotransmitters. Although nitric oxide has ben investigated as a neurotransmitter in other tissues, no published studies have examined the role of nitric oxide in the vestibular system. Neuronal NADPH-dlaphorase has been characterized as a nitric oxide synthase. This enzyme catalyzes the conversion of L-arginine to l-citrulline, producing nitric oxide during the reaction. We used a histochemical stain characterized by Hope et al. (Proc Natl Acad Sci 1991;88:2811) as specific for neuronal nitric oxide synthase to localize the enzyme in the rat vestibular system. An Immunocytochemical stain was used to examine rat Inner ear tissue for the presence of the enzyme's end product, l-citrulline, thereby demonstrating nitric oxide synthase activity. Staining of vestibular ganglion sections showed nitric oxide synthase presence and activity in ganglion cells and nerve fibers. These results Indicate the presence of active nitric oxide synthase in these tissues and suggest modulation of vestibular neurotransmission by nitric oxide.


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