Calcitonin Gene-Related Peptide Receptor Inhibition Reduces Neuronal Activity Induced by Prolonged Increase in Nitric Oxide in the Rat Spinal Trigeminal Nucleus

Cephalalgia ◽  
2009 ◽  
Vol 29 (4) ◽  
pp. 408-417 ◽  
Author(s):  
S Kulchitsky ◽  
MJM Fischer ◽  
K Messlinger

Infusion of nitric oxide (NO) donors is known to induce delayed attacks of migraine and cluster headache or aggravate tension-type headaches in patients suffering from these primary headaches. Previously we have reported that infusion of NO donors in the rat causes delayed neuronal activity in the spinal trigeminal nucleus, which parallels the above clinical observations. Suggesting that endogenous NO production is involved in the generation of primary headaches, we used this animal model of meningeal nociception to determine whether a prolonged increase in NO levels causes an increase in neuronal activity. In anaesthetized rats spinal trigeminal neurons with afferent input from the exposed dura were recorded. Continuous intravenous infusion of the NO donors sodium nitroprusside (25 μg/kg/h) or glycerol trinitrate (250 μg/ kg/h) for 2h induced a persisting increase in neuronal activity but no change in systemic blood pressure. In this activated trigeminal system the calcitonin gene-related peptide (CGRP) receptor antagonist BIBN4096BS (900 μg/ kg) was infused. Spinal trigeminal activity was significantly reduced within minutes and to a similar extent as previously reported in animals not treated with NO. Slow continuous NO infusion may be a model of the active headache phase, and inhibition of CGRP receptors can reverse the induced neuronal activity.

2020 ◽  
Vol 21 (11) ◽  
pp. 4049
Author(s):  
Hui Shu ◽  
Sufang Liu ◽  
Yuanyuan Tang ◽  
Brian L. Schmidt ◽  
John C. Dolan ◽  
...  

Migraine is commonly reported among patients with temporomandibular disorders (TMDs), especially myogenic TMD. The pathophysiologic mechanisms related to the comorbidity of the two conditions remain elusive. In the present study, we combined masseter muscle tendon ligation (MMTL)-produced myogenic TMD with systemic injection of nitroglycerin (NTG)-induced migraine-like hypersensitivity in mice. Facial mechanical allodynia, functional allodynia, and light-aversive behavior were evaluated. Sumatriptan, an FDA-approved medication for migraine, was used to validate migraine-like hypersensitivity. Additionally, we examined the protein level of calcitonin gene-related peptide (CGRP) in the spinal trigeminal nucleus caudalis using immunohistochemistry. We observed that mice with MMTL pretreatment have a prolonged NTG-induced migraine-like hypersensitivity, and MMTL also enabled a non-sensitizing dose of NTG to trigger migraine-like hypersensitivity. Systemic injection of sumatriptan inhibited the MMTL-enhanced migraine-like hypersensitivity. MMTL pretreatment significantly upregulated the protein level of CGRP in the spinal trigeminal nucleus caudalis after NTG injection. Our results indicate that a pre-existing myogenic TMD can upregulate NTG-induced trigeminal CGRP and enhance migraine-like hypersensitivity.


2004 ◽  
Vol 286 (1) ◽  
pp. H230-H239 ◽  
Author(s):  
Yuan-Lin Dong ◽  
Sujatha Vegiraju ◽  
Madhu Chauhan ◽  
Pandu R. R. Gangula ◽  
Gary D. V. Hankins ◽  
...  

Calcitonin gene-related peptide (CGRP), one of the most potent endogenous vasodilators known, has been implicated in vascular adaptations and placental functions during pregnancy. The present study was designed to examine the existence of CGRP-A receptor components, the calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein 1 (RAMP1), in the human placenta and the vasoactivity of CGRP in the fetoplacental circulation. Immunofluorescent staining of the human placenta in term labor using polyclonal anti-CRLR and RAMP1 antibodies revealed that labeling specifically concentrated in the vascular endothelium and the underlying smooth muscle cells in the umbilical artery/vein, chorionic artery/vein, and stem villous vessels as well as in the trophoblast layer of the placental villi. In vitro isometric force measurement showed that CGRP dose dependently relaxes the umbilical artery/vein, chorionic artery/vein, and stem villous vessels. Furthermore, CGRP-induced relaxation of placental vessels are inhibited by a CGRP receptor antagonist (CGRP8–37), ATP-sensitive potassium (KATP) channel blocker (glybenclamide), and cAMP-dependent protein kinase A inhibitor (Rp-cAMPS) and partially inhibited by a nitric oxide inhibitor ( Nω-nitro-l-arginine methyl ester). We propose that CGRP may play a role in the control of human fetoplacental vascular tone, and the vascular dilations in response to CGRP may involve activation of KATP channels, cAMP, and a nitric oxide pathway.


2000 ◽  
Vol 279 (4) ◽  
pp. H1654-H1660 ◽  
Author(s):  
Yasushi Takahashi ◽  
Maartje De Vroomen ◽  
Christine Roman ◽  
Michael A. Heymann

Fetal pulmonary blood flow is regulated by various vasoactive substances. One, calcitonin gene-related peptide (CGRP), increases pulmonary blood flow. We examined four key physiological mechanisms underlying this response using the blocker drugs CGRP receptor blocker (CGRP8–37), nitric oxide synthase inhibitor [ N ω-nitro-l-arginine (l-NNA)], adenosine triphosphate-dependent potassium (KATP) channel blocker (glibenclamide), and cyclooxygenase inhibitor (indomethacin) in 17 near-term fetal sheep. Catheters were placed in the left (LPA) and main pulmonary arteries, and an ultrasonic flow transducer was placed around the LPA to measure flow continuously. CGRP was injected directly into the LPA (mean 1.02 μg/kg) before and after blockade, and responses to CGRP were statistically compared. Before blockade, CGRP increased LPA blood flow from 23 ± 25 to 145 ± 77 ml/min (means ± SD), and these increases were significantly attenuated by CGRP8–37( n = 6; 91% inhibition), l-NNA ( n = 6; 86% inhibition), and glibenclamide ( n = 6; 69% inhibition). No significant changes were found with indomethacin ( n = 6; 4% inhibition). Thus, in the fetal pulmonary circulation, CGRP increases pulmonary blood flow not only through its specific receptor but also, in part, through nitric oxide release and KATP channel activation.


Sign in / Sign up

Export Citation Format

Share Document