scholarly journals Unilateral Corneal Insult Also Alters Sensory Nerve Activity in the Contralateral Eye

2021 ◽  
Vol 8 ◽  
Author(s):  
Carolina Luna ◽  
Susana Quirce ◽  
Adolfo Aracil-Marco ◽  
Carlos Belmonte ◽  
Juana Gallar ◽  
...  
Keyword(s):  
Lacrimal Gland ◽  
Ocular Surface ◽  
Guinea Pigs ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Nerve Lesion ◽  
Corneal Surgery ◽  
Nerve Activity ◽  
Direct Demonstration ◽  
Contralateral Eye

After the unilateral inflammation or nerve lesion of the ocular surface, the ipsilateral corneal sensory nerve activity is activated and sensitized, evoking ocular discomfort, irritation, and pain referred to the affected eye. Nonetheless, some patients with unilateral ocular inflammation, infection, or surgery also reported discomfort and pain in the contralateral eye. We explored the possibility that such altered sensations in the non-affected eye are due to the changes in their corneal sensory nerve activity in the contralateral, not directly affected eye. To test that hypothesis, we recorded the impulse activity of the corneal mechano- and polymodal nociceptor and cold thermoreceptor nerve terminals in both eyes of guinea pigs, subjected unilaterally to three different experimental conditions (UV-induced photokeratitis, microkeratome corneal surgery, and chronic tear deficiency caused by removal of the main lacrimal gland), and in eyes of naïve animals ex vivo. Overall, after unilateral eye damage, the corneal sensory nerve activity appeared to be also altered in the contralateral eye. Compared with the naïve guinea pigs, animals with unilateral UV-induced mild corneal inflammation, showed on both eyes an inhibition of the spontaneous and stimulus-evoked activity of cold thermoreceptors, and increased activity in nociceptors affecting both the ipsilateral and the contralateral eye. Unilateral microkeratome surgery affected the activity of nociceptors mostly, inducing sensitization in both eyes. The removal of the main lacrimal gland reduced tear volume and increased the cold thermoreceptor activity in both eyes. This is the first direct demonstration that unilateral corneal nerve lesion, especially ocular surface inflammation, functionally affects the activity of the different types of corneal sensory nerves in both the ipsilateral and contralateral eyes. The mechanisms underlying the contralateral affectation of sensory nerves remain to be determined, although available data support the involvement of neuroimmune interactions. The parallel alteration of nerve activity in contralateral eyes has two main implications: a) in the experimental design of both preclinical and clinical studies, where the contralateral eyes cannot be considered as a control; and, b) in the clinical practice, where clinicians must consider the convenience of treating both eyes of patients with unilateral ocular conditions to avoid pain and secondary undesirable effects in the fellow eye.

Renal sympathetic nerve activity modulates afferent renal nerve activity by PGE2-dependent activation of α1- and α2-adrenoceptors on renal sensory nerve fibers

2007 ◽  
Vol 293 (4) ◽  
pp. R1561-R1572 ◽  
Author(s):  
Ulla C. Kopp ◽  
Michael Z. Cicha ◽  
Lori A. Smith ◽  
Jan Mulder ◽  
Tomas Hökfelt
Keyword(s):  
Sensory Nerve ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Renal Sympathetic Nerve Activity ◽  
Pelvic Wall ◽  
Renal Nerve Activity ◽  
Pelvic Perfusion ◽  
Renal Sympathetic

Increasing efferent renal sympathetic nerve activity (ERSNA) increases afferent renal nerve activity (ARNA). To test whether the ERSNA-induced increases in ARNA involved norepinephrine activating α-adrenoceptors on the renal sensory nerves, we examined the effects of renal pelvic administration of the α1- and α2-adrenoceptor antagonists prazosin and rauwolscine on the ARNA responses to reflex increases in ERSNA (placing the rat's tail in 49°C water) and renal pelvic perfusion with norepinephrine in anesthetized rats. Hot tail increased ERSNA and ARNA, 6,930 ± 900 and 4,870 ± 670%·s (area under the curve ARNA vs. time). Renal pelvic perfusion with norepinephrine increased ARNA 1,870 ± 210%·s. Immunohistochemical studies showed that the sympathetic and sensory nerves were closely related in the pelvic wall. Renal pelvic perfusion with prazosin blocked and rauwolscine enhanced the ARNA responses to reflex increases in ERSNA and norepinephrine. Studies in a denervated renal pelvic wall preparation showed that norepinephrine increased substance P release, from 8 ± 1 to 16 ± 1 pg/min, and PGE2 release, from 77 ± 11 to 161 ± 23 pg/min, suggesting a role for PGE2 in the norepinephrine-induced activation of renal sensory nerves. Prazosin and indomethacin reduced and rauwolscine enhanced the norepinephrine-induced increases in substance P and PGE2. PGE2 enhanced the norepinephrine-induced activation of renal sensory nerves by stimulation of EP4 receptors. Interaction between ERSNA and ARNA is modulated by norepinephrine, which increases and decreases the activation of the renal sensory nerves by stimulating α1- and α2-adrenoceptors, respectively, on the renal pelvic sensory nerve fibers. Norepinephrine-induced activation of the sensory nerves is dependent on renal pelvic synthesis/release of PGE2.

scholarly journals Inhibition of guinea-pig and human sensory nerve activity and the cough reflex in guinea-pigs by cannabinoid (CB2 ) receptor activation

2003 ◽  
Vol 140 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Hema J Patel ◽  
Mark A Birrell ◽  
Natascia Crispino ◽  
David J Hele ◽  
Priya Venkatesan ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Sensory Nerve ◽  
Receptor Activation ◽  
Cb2 Receptor ◽  
Nerve Activity ◽  
Cough Reflex

Abstract MP21: Circadian Cycle Exaggerates Sympathoexcitatory Responses To Activation Of Chemosensitive Renal Sensory Nerves

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Leon J DeLalio ◽  
Sean D Stocker
Keyword(s):  
Sympathetic Nerve Activity ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Circadian Cycle ◽  
Nerve Activity ◽  
Arterial Infusion ◽  
Arterial Blood ◽  
Inactive Phase ◽  
The Impact ◽  
Circadian Patterns

Renal sensory nerves contribute to hypertension and renal dysfunction in chronic kidney disease. Selective chemokines (e.g., bradykinin or capsaicin) activate renal sensory nerves and produce reflexive efferent sympathetic nerve activity (SNA) and arterial blood pressure (ABP) responses. SNA, ABP, and renal function exhibit circadian patterns; yet the impact of circadian cycle on chemosensitive responses is unknown. We hypothesized that SNA and hemodynamic responses would be greater during the active phrase or nighttime versus the inactive phase or daytime. In Inactin anesthetized rats, simultaneous renal and splanchnic SNA and ABP were measured during intrarenal arterial infusion of capsaicin or bradykinin (0.1 μM - 30.0 μM; 50 μl over 15 s) at nighttime (N; 20:00-04:00; n= 12M, 10F) versus daytime (D; 09:00-16:00; n= 8M, 8F). Baseline mean ABP was significantly elevated during nighttime (N: 104±2 mmHg; D: 97±2 mmHg, p=0.04). Intrarenal capsaicin infusion produced concentration-dependent increases in renal and splanchnic SNA. Renal SNA increased more at nighttime versus daytime at 10 μM (N: 723±136 vs D: 409±79 %; p=0.03) and 30 μM (N: 826±181 vs D: 509±80 %; p=0.03). Similarly, splanchnic SNA was greater during nighttime versus daytime at 10 μM (N: 501±117 vs D: 204±53 %, p=0.03) and 30 μM (N: 537±101 vs D: 295±68 %; p=0.03). However, ABP responses were similar between nighttime versus daytime (30uM: 7±1 vs 6±1 mmHg, respectively). Intrarenal infusion of bradykinin produced concentration-dependent increases in renal and splanchnic SNA. Renal SNA increased more at nighttime versus daytime at 10 μM (N: 1773±216 vs D: 1249±112 %; p=0.01) and 30 μM (N: 2605±263 vs D: 1783±163 %; p=0.001). Similarly, splanchnic SNA was exaggerated at nighttime versus daytime at 0.1 μM (N: 163±65 vs D: 0±0 %; p=0.02), 1.0 μM (N: 566±114 vs D: 184±52 %; p=0.005), 10 μM (N: 1110±193 vs D: 583±87 %; p=0.006) and 30 μM (N: 2008±193 vs D: 1044±162 %; p<0.001). ABP response were similar between nighttime versus daytime at 30 μM (10±2 vs 6±1 mmHg, respectively). Circadian cycle exaggerates sympathoexcitatory responses produced by chemosensitive renal sensory nerve activation.

scholarly journals Effectiveness of 0.66% Povidone-Iodine Eye Drops on Ocular Surface Flora before Cataract Surgery: A Nationwide Microbiological Study

2021 ◽  
Vol 10 (10) ◽  
pp. 2198
Author(s):  
Rosario Musumeci ◽  
Pasquale Troiano ◽  
Marianna Martinelli ◽  
Matteo Piovella ◽  
Claudio Carbonara ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Ocular Surface ◽  
Povidone Iodine ◽  
Bacterial Species ◽  
Bacterial Flora ◽  
Bacterial Load ◽  
Controlled Study ◽  
Eye Drops ◽  
Microbiological Analysis ◽  
Contralateral Eye

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.

scholarly journals Plasma calcitonin gene-related peptide is increased prior to obesity, and sensory nerve desensitization by capsaicin improves oral glucose tolerance in obese Zucker rats

2005 ◽  
Vol 153 (6) ◽  
pp. 963-969 ◽  
Author(s):  
Dorte X Gram ◽  
Anker J Hansen ◽  
Michael Wilken ◽  
Torben Elm ◽  
Ove Svendsen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Glucose Tolerance ◽  
Sensory Nerve ◽  
Zucker Rats ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Nerve Activity ◽  
Calcitonin Gene ◽  
Obese Rats ◽  
Obese Zucker Rats

Objective: It has earlier been demonstrated that capsaicin-induced desensitization improves insulin sensitivity in normal rats. However, whether increased capsaicin-sensitive nerve activity precedes the onset of insulin resistance in diet-induced obesity – and therefore might be involved in the pathophysiology – is not known. Further, it is of relevance to investigate whether capsaicin desensitization improves glycaemic control even in obese individuals and we therefore chose the obese Zucker rats to test this. Design and methods: Plasma levels of calcitonin gene-related peptide (CGRP; a marker of sensory nerve activity) was assessed in 8-week-old Zucker rats. To investigate whether capsaicin desensitization (100 mg/kg at 9 weeks of age) would also ameliorate glycaemia in this non-diabetic model, we assessed oral glucose tolerance at 7 weeks after capsaicin. Results: It was found that plasma CGRP levels were elevated in obese Zucker rats prior to the onset of obesity (16.1±3.4 pmol/l in pre-obese Zucker rats vs 6.9±1.1 pmol/l in lean littermates; P = 0.015) despite similar body weights. Furthermore, capsaicin desensitization reduced both fasting blood glucose (4.3±0.2 mmol/l vs 5.1±0.2 mmol/l in controls; P = 0.050) as well as the mean blood glucose level during an oral glucose tolerance test (OGTT) (6.8±0.3 mmol/l vs 8.6±0.5 mmol/l in control obese rats; P = 0.024) whereas the plasma insulin levels during the OGTT were unchanged. However this did not lead to an improvement in insulin resistance or to a reduction of tissue triglyceride accumulation in muscle or liver. Conclusion: We concluded that capsaicin-induced sensory nerve desensitization improves glucose tolerance in Zucker rats. Since, in this study, plasma CGRP levels, a marker of sensory nerve activity, were increased in the pre-obese rats, our data support the hypothesis that increased activity of sensory nerves precedes the development of obesity and insulin resistance in Zucker rats.

MUC19 expression in human ocular surface and lacrimal gland and its alteration in Sjögren syndrome patients

2008 ◽  
Vol 86 (2) ◽  
pp. 403-411 ◽  
Author(s):  
D.F. Yu ◽  
Y. Chen ◽  
J.M. Han ◽  
H. Zhang ◽  
X.P. Chen ◽  
...  
Keyword(s):  
Lacrimal Gland ◽  
Ocular Surface ◽  
Sjögren Syndrome ◽  
Sjogren Syndrome

Abstract MP45: Deletion Of The Transient Receptor Vanilloid-1 (TRPV1) Channel In Rats Attenuates 2 Kidney 1 Clip Hypertension

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sean D Stocker ◽  
Leon J DeLalio
Keyword(s):  
Heart Rate ◽  
Renovascular Hypertension ◽  
Sensory Nerve ◽  
Experimental Models ◽  
Sensory Nerves ◽  
Male Rats ◽  
Wild Type ◽  
Renal Nerve ◽  
Trpv1 Channels ◽  
Arterial Blood

Renal denervation lowers arterial blood pressure (ABP) in both clinical populations and multiple experimental models of hypertension. This therapeutic effect is partly attributed to the removal of overactive renal sensory nerves that increase sympathetic efferent activity and ABP. Renal sensory nerves highly express TRPV1 channels, and administration of the TRPV1 agonist capsaicin increases renal sensory nerve activity. However, the extent by which TRPV1 channels directly contribute to renal nerve dependent models of hypertension has not been tested. To test this hypothesis, we generated a novel TRPV1 -/- rat using CRISPR/Cas9 and deletion of exon 3. Male and female TRPV1 -/- and wild-type littermates (8-12 weeks) were instrumented with telemetry. At 2 weeks later, renovascular hypertension via renal stenosis was produced by placement of a PTFE cuff (0.16 x 0.22 inches, 1mm long) around the right renal artery. Male TRPV1 -/- and wild-type rats had no differences in baseline mean ABP (99±2 vs 98±3 mmHg, respectively; n=7-9) or heart rate (390±7 vs 400±8 bpm, respectively). Renal stenosis significantly increased mean ABP in both groups; however, mean ABP was significantly lower at Day 28 in male TRPV1 -/- versus wild-type rats (125±8 vs 155±2 mmHg, respectively: P<0.01). Ganglionic blockade with chlorisondamine (2.5mg/kg, sc) at Day 28 produced a smaller fall in mean ABP of male TRPV1 -/- versus wild-type rats (-53±4 vs -86±3 mmHg, respectively; P<0.001). On the other hand, female TRPV1 -/- and wild-type rats had no differences in baseline mean ABP (102±2 vs 104±1 mmHg, respectively; n=6-9) or heart rate (419±8 vs 410±7 bpm, respectively). Renal stenosis significantly increased mean ABP in both groups; however, there were no differences at Day 28 between female TRPV1 -/- versus wild-type rats (117±8 vs 122±6 mmHg, respectively). Moreover, the increase in mean ABP was smaller in females versus males. The ganglionic blocker chlorisondamine produced similar depressor responses in female TRPV1 -/- versus wild-type rats (-64±7 vs -65±7 mmHg, respectively). These findings illustrate a sex difference in renovascular hypertension in rats, but importantly indicate that TRPV1 channels contribute to the established phase of renovascular hypertension in male rats.

Modulation of sympathetic nerve activity during posthandgrip muscle ischemia in humans

1994 ◽  
Vol 266 (1) ◽  
pp. H79-H83 ◽  
Author(s):  
C. A. Ray ◽  
N. H. Secher ◽  
A. L. Mark
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Sensory Nerve ◽  
Vascular Occlusion ◽  
Voluntary Contraction ◽  
Central Command ◽  
Isometric Handgrip ◽  
Nerve Activity ◽  
Muscle Ischemia

To evaluate modulation of muscle sympathetic nerve activity (MSNA) during posthandgrip muscle ischemia (PHGMI), subjects performed 2 min of isometric handgrip at 33% of maximal voluntary contraction (MVC) followed by 2 min of PHGMI produced by forearm vascular occlusion. The response to PHGMI was studied in the absence and again during the addition of contralateral rhythmic handgrip (RHG; 40 times/min) at 15% (n = 6) and 30% (n = 10) MVC during the second minute of the PHGMI. Additionally, to isolate the effect of central command, response to PHGMI was studied during attempted RHG after sensory nerve blockade (n = 5). RHG for 2 min at 15 and 30% MVC and attempted RHG for 2 min did not increase MSNA. Isometric handgrip elicited an 130 +/- 48% increase in MSNA (P < 0.05), which was maintained during PHGMI. RHG at 15 and 30% MVC elicited an attenuation of MSNA (-10 +/- 7% and -14 +/- 6%, respectively) when performed during the second minute of PHGMI (P < 0.05). In contrast, attempted RHG did not significantly affect MSNA during PHGMI. The findings demonstrate modulation of MSNA during activation of the muscle metaboreflex. The attenuation of metaboreceptor-mediated increases in MSNA appear to be the result of mechanosensitive muscle afferents and not central command.

Very Early Neurophysiological Study in Guillain-Barre Syndrome

2018 ◽  
Vol 80 (1-2) ◽  
pp. 100-105 ◽  
Author(s):  
Jiaoting Jin ◽  
Fangfang Hu ◽  
Xing Qin ◽  
Xuan Liu ◽  
Min Li ◽  
...  
Keyword(s):  
Nerve Conduction ◽  
Nerve Conduction Velocity ◽  
Tibial Nerve ◽  
Early Stage ◽  
Motor Nerve ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Motor Nerve Conduction ◽  
Abnormal Rate ◽  
Motor Nerves

Purpose: The diagnosis of Guillain-Barre syndrome (GBS) in the very early stage may be challenging. Our aim was to report the neurophysiological abnormalities in GBS within 4 days of clinical onset. We expected that GBS will be diagnosed by the assistance of neurophysiological study in the very early stage. Methods: We prospectively recruited patients with a diagnosis of GBS discharged from First Affiliated Hospital of Xi’an Jiaotong University and Xi Jing Hospital. Patients were classified into 3 groups according to the onset of symptoms to electromyography examination interval (OEI). The neurophysiological findings were carried out using standard procedures. All patients were examined by the same experienced neurophysiologist. Results: There were not significant group differences in abnormal rate, distal motor latency (DML), motor nerve conduction velocity (MNCV), F response (FR), compound muscle action potential (CMAP), conduction block (CB), sensory nerve action potential (SNAP), and sensory nerve conduction velocity among OEI ≤4 days, 4< OEI ≤10 days, and OEI > 10 days groups. Motor nerves were more affected than sensory nerves in neurophysiological presentation in very early stage patients. The difference of motor nerves and sensory nerves was statistically significant in lower limbs, but was not in upper limbs. In motor nerve conduction studies, the abnormal rate of DML, MNCV, FR, CB was more common seen in ulnar and peroneal nerve than median and tibial nerve, the abnormal rate of CMAP was the same in ulnar, median, peroneal and tibial nerve. In sensory nerve conduction studies, the abnormal rate of ulnar nerve and median nerve was higher than the superficial peroneal nerve and sural nerve. The OEI was not correlated with the SNAP decrease rate of median (r = 0.10, p = 0.23) and ulnar (r = 0.26, p = 0.06) but was statistically correlated with sural SNAP decrease rate (r = 0.29, p = 0.04). The sural-sparing pattern phenomenon was the most commonly discovered phenomenon in very early stage patients (OEI ≤4 days), followed by patients with 4< OEI ≤10 days, ultimately found in patients with OEI > 10 days. Conclusions: We suggest performing neurophysiological examination as soon as possible for suspected GBS patients, particularly focusing on multi-spots inspection of ulnar and peroneal nerves, and paying close attention to sural-sparing patterns.

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