Calcitonin gene-related peptide (CGRP) and its receptor components in human and rat spinal trigeminal nucleus and spinal cord at C1-level

<p>Abstract</p> <p>Background</p> <p>Calcitonin gene-related peptide (CGRP) has a key role in migraine pathophysiology and is associated with activation of the trigeminovascular system. The trigeminal ganglion, storing CGRP and its receptor components, projects peripheral to the intracranial vasculature and central to regions in the brainstem with Aδ- and C-fibers; this constitutes an essential part of the pain pathways activated in migraine attacks. Therefore it is of importance to identify the regions within the brainstem that processes nociceptive information from the trigeminovascular system, such as the spinal trigeminal nucleus (STN) and the C1-level of the spinal cord. Immunohistochemistry was used to study the distribution and relation between CGRP and its receptor components - calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) - in human and rat STN and at the C1-level, using a set of newly well characterized antibodies. In addition, double-stainings with CGRP and myelin basic protein (MBP, myelin), synaptophysin (synaptic vesicles) or IB4 (C-fibers in general) were performed.</p> <p>Results</p> <p>In the STN, the highest density of CGRP immunoreactive fibers were found in a network around fiber bundles in the superficial laminae. CLR and RAMP1 expression were predominately found in fibers in the spinal trigeminal tract region, with some fibers spanning into the superficial laminae. Co-localization between CGRP and its receptor components was not noted. In C1, CGRP was expressed in fibers of laminae I and II. The CGRP staining was similar in rat, except for CGRP positive neurons that were found close to the central canal. In C1, the receptor components were detected in laminae I and II, however these fibers were distinct from fibers expressing CGRP as verified by confocal microscopy.</p> <p>Conclusions</p> <p>This study demonstrates the detailed expression of CGRP and its receptor components within STN in the brainstem and in the spinal cord at C1-level, and shows the possibility of CGRP acting postjunctionally in these areas putatively involved in primary headaches.</p

'Molecular zips': Evidence of the interdigitation of layers in Langmuir-Blodgett films of an optically non-linear dye and a compatible spacer

Second-harmonic generation (SHG) from alternate-layer Langmuir-Blodgett (LB) films of (E)-4-[2-(4-methoxynaphthyl)-ethenyl]-N-docosylquinolinium bromide (dye) and N-octadecyl-4-methylquinolinium bromide (spacer) increases quadratically with the number of bilayers with a susceptibility of chi(zzz)((2)) pm V-1 at 1.064 mu m. The lower layers show significant variation of the second-harmonic intensity across the surface whereas the thicker films provide evidence of self-healing with a maximum variation of +/- 10% across 90% of the area studied. The thickness and the real and imaginary parts of the dielectric permittivity from the surface plasmon resonance (SPR) at lambda = 532 nm are l = 31.8 Angstrom, epsilon(r) = 2.44 and epsilon(i) = 0.23 for monolayer films of the dye and l = 42.9 Angstrom, epsilon(i) = 2.85 and epsilon(i) = 0.29 for the dye-spacer bilayer. The dye and spacer have compatible interlocking geometries and the diminished depth of the spacer layer, 11 Angstrom by difference, may be explained by interdigitation of the alkyl chains at the interface. The bilayer thickness of 42.9 Angstrom from SPR is in agreement with the d-spacing of 42 +/- 1 Angstrom from X-ray synchrotron diffraction