Calcitonin Gene Related Peptide

Background Recent studies on migraineurs and our own animal experiments have revealed that pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) has an important role in activation of the trigeminovascular system. The aim of this study was to determine the PACAP-38-like immunoreactivity (LI) in the plasma of healthy subjects, and parallel with the calcitonin gene-related peptide (CGRP)-LI in migraine patients in the ictal and interictal periods. Methods A total of 87 migraineurs and 40 healthy control volunteers were enrolled in the examination. Blood samples were collected from the cubital veins in both periods in 21 patients, and in either the ictal or the interictal period in the remaining 66 patients, and were analysed by radioimmunoassay. Results A significantly lower PACAP-38-LI was measured in the interictal plasma of the migraineurs as compared with the healthy control group ( p < 0.011). In contrast, elevated peptide levels were detected in the ictal period re...

A combination of immunocytochemical and electron microscopic methods were employed to assess the organization of the trigeminal (V) spinal tract in adult rats. Immunostaining was employed at the light microscopic level to selectively label large myelinated (by using antibodies against neurofilament protein) and small unmyelinated (by using antibodies against calcitonin gene-related peptide) primary afferents. In addition, the plant lectin Bandeiraea simplicifolia-I was employed to histochemically label small unmyelinated primary afferents. Results from these experiments indicated that larger myelinated axons were distributed throughout the cross-sectional extent of the V spinal tract (TrV), whereas smaller fibers were most numerous just below the pial surface. These results were confirmed with quantitative electron microscopy which demonstrated that the central portion of the V sensory root and TrV were composed primarily of larger myelinated fibers, whereas the periphery of the root and the portion of TrV just below the pial surface contained a higher percentage of smaller myelinated and unmyelinated axons. When considered together with results regarding the birthdates of neurochemically defined classes of V ganglion cells (White et al. [1994] J. Comp. Neurol. 350:397-411), these results suggest that TrV is laid down in a chronotopic fashion with the first axons forming its deeper portion and later arriving axons being added more superficially.

Objectives To investigate the formulation of the peptide-based antagonist (34Pro,35Phe)CGRP27–37, of the human calcitonin gene-related peptide (CGRP) receptor as a potential nasally delivered migraine treatment. Methods Peptide sequences were prepared using automated methods and purified by preparative HPLC. Their structure and stability were determined by LC-MS. Antagonist potency was assessed by measuring CGRP-stimulated cAMP accumulation in SK-N-MC, cells and in CHO cells overexpressing the human CGRP receptor. In vivo activity was tested in plasma protein extravasation (PPE) studies using Evans blue dye accumulation. Peptide-containing chitosan microparticles were prepared by spray drying. Key findings (34Pro,35Phe)CGRP27–37 exhibited a 10-fold increased affinity compared to αCGRP27–37. Administration of (34Pro,35Phe)CGRP27–37 to mice led to a significant decrease in CGRP-induced PPE confirming antagonistic properties in vivo. There was no degradation of (34Pro,35Phe)CGRP27–37 a...

To evaluate the efficacy and tolerability of telcagepant when co-administered with ibuprofen or acetaminophen for the acute treatment of migraine. Telcagepant is an oral calcitonin gene-related peptide receptor antagonist which is being evaluated for the acute treatment of migraine. Combining telcagepant with analgesics that have a different mechanism of action could produce greater efficacy. Randomized, double-blind, placebo-controlled study. Patients were randomized to treat a moderate or severe migraine headache with either telcagepant 280 mg + ibuprofen 400 mg (N = 171), telcagepant 280 mg + acetaminophen 1000 mg (N = 171), telcagepant 280 mg (N =170), or placebo (N = 171). The primary efficacy endpoint was 2-hour pain freedom. The study had approximately 88% power to detect an additive effect of at least 15 percentage points (telcagepant combination vs telcagepant monotherapy) and 48% power to detect an additive effect of at least 10 percentage points. Safety and tolerability were assessed by adverse events and laboratory tests. The percentages of patients with 2-hour pain freedom were greater in each active treatment group compared to placebo (P < .001): telcagepant + ibuprofen = 35.2%, telcagepant + acetaminophen = 38.3%, telcagepant = 31.2%, placebo = 10.9%. No significant differences were seen for either of the combination groups vs telcagepant monotherapy, but both were numerically larger than telcagepant monotherapy. All the active treatments were generally well tolerated. The percentage of patients reporting any adverse event within 48 hours was higher in the active treatment groups than placebo: telcagepant + ibuprofen = 30.3%, telcagepant + acetaminophen = 31.6%, telcagepant = 24.8%, placebo = 18.2%. The most common adverse events reported by ≥ 4 patients in one or more of the treatment groups that included telcagepant were fatigue, nausea, dizziness, somnolence, dry mouth, and tremor. The combination of telcagepant 280 mg with either ibuprofen 400 mg or acetaminophen 1000 mg did not show a statistically significant difference from telcagepant alone. Numerically greater treatment effects in the combination treatment groups over the telcagepant 280 mg monotherapy suggest that telcagepant combination treatments may merit further evaluation in studies powered to detect smaller additive benefits. (Clinicaltrials.gov; NCT00758836).

Objective To measure the concentrations of calcitonin gene-related peptide(CGRP) and substance P(SP) in blood of rats before and after chronic constriction injury of trigeminal nerve,and to assess their significance in the pathogenesis of trigeminal neuralgia.Methods Eighteen male Sprague-Dawley(SD) rats were randomly assigned into 3 groups(6 each): surgical group(group A),sham operation group(group B) and control group(group C).The right infraorbital nerve(ION) of rats in group A was lightly ligated with chromic catgut to induce chronic constriction injury(CCI).In group B,the ION was exposed only with the same procedure but without ligation.And the rats in group C received no operation.The response of rats to mechanical irritation was observed after operation.Blood samples were taken from all the 3 group of rats to measure the concentration of CGRP and SP by using enzyme linked immunosorbent assay(ELISA) before operation and 3,9 and 15 days after operation.Results Compared with gro...