Major Neuroanatomical And Neurochemical Substrates Involved In Primary Headaches

Neuroanatomical structures involved in head pain are primarily the sensory distribution of four cranial nerves: the trigeminal-and to a lesser extent, facial, glossopharyngeal, and vagus-as well as the terminations of the upper three cervical nerves.In addition, various pain sensitive cranial structures including the scalp and its blood supply, the head and neck muscles, intracranial and meningeal arteries, and dura mater including the venous sinuses are the major anatomical substrates of various types of headaches. Although brain tumors, different types of hemorrhage, hypertension, and meningitis may present as a headache, the migraine, cluster, and tension headaches are the three major types of primary headaches. Current opinion suggests a primary central nervous system activation may initiate a migraine. Several triggering factors such as disturbances of brain oxygenation and metabolism, alterations in the serotonin levels, low levels of brain tissue magnesium, altered transport of ions across the cell membrane, abnormal mitochondrial energy metabolism, and genetic abnormalities including mutations of the P/Q type calcium channel gene, Na+/K+ pump ATP1A2, or sodium channel Nav1.1 mutations have been linked to the pathogenesis of migraines. Patients with mutations in the calcium channel gene are more sensitive to environmental factors, which results in a wave of cortical spreading depression in the patient after the attack is initiated.Moreover, several recent clinical and diagnostic studies indicate a dysfunction of the brainstem periaqueductal gray matter during migraine, or initiation of migraine by activation of the brainstem including the dorsal rostral and midline pons. Consistent with this, an active locus in the posterior hypothalamus has been implicated in cluster headache (CH). The headache phase involves the activation of the trigeminovascular system and possibly dilatation of the cranial blood vessels presumably mediated by the release of vasoactive substances and neuropeptides including the calcitonin gene-related peptide (CGRP). Increased serum CGRP levels were detected during migraine and CH. In addition, in CH, there is a release of parasympathetic peptide, vasoactive intestinal peptide. Currently, inhibiting the release of vasoactive substances and neuropeptides including the CGRP or nitric oxide, or blocking their receptors in the neuroanatomical substrates of head pain is a major focus in treatment of headaches. © 2010 by Nova Science Publishers, Inc. All rights reserved

Neuropeptides And Other Chemical Mediators, And The Role Of Antiinflammatory Drugs In Primary Headaches

Primary headaches including the migraine, cluster, and tension headaches are common neurological disorders which cause pain and disability to the patients. The pathomechanism of migraine is not very well understood however, current clinical findings indicate a possible primary brain disorder due to activation of the brain and brainstem as triggers for migraine. The headache phase of migraine may be due to activation of the peripheral nerves including the trigeminal nerve and others innervating the cranial blood vessels and release of vasoactive substances including the calcitonin generelated peptides (CGRP), possibly leading to vasodilation and brainstem activation. Several of our studies in an experimental model of pain using electrical stimulation of the trigeminal ganglion in rats focused on various neuropeptides release from the peripheral and central trigeminal nerve terminals, however, clinically only the CGRP in migraine and CGRP and vasoactive intestinal peptide (VIP) in cluster headache were found in patient\u27s blood. Although several drugs are used in the treatment of migraine, the non-steroid anti-inflammatory drugs (NSAIDs) and the triptan family of drugs are the first choice drugs recommended for the treatment of acute migraine headache. Although clinically very few studies detected other vasoactive/inflammatory molecules in the blood of migraine patients, sensitization of peripheral axons can involve many inflammatory mediators affecting the peripheral tissue substrates of pain. Moreover, central sensitization in the trigeminal nucleus can also contribute to additional pain responses. This article reviews neuropeptides and other molecules involved in primary headaches and major drugs proposed for their treatment in recent years. © 2010 Bentham Science Publishers Ltd

Frontiers in Vitamin Research: New Antibodies, New Data

Since 2004, the anatomical distribution of vitamins in the monkey brain, studied using immunohistochemical techniques and new tools (specific antisera that discriminate different vitamins reasonably well), has been an ongoing research field. The visualization of immunoreactive structures containing vitamins (folic acid, riboflavin, thiamine, pyridoxal, and vitamin C) has recently been reported in the monkey brain (Macaca fascicularis), all these vitamins showing a restricted or very restricted distribution. Folic acid, thiamine, and riboflavin have only been observed in immunoreactive fibers, vitamin C has only been found in cell bodies (located in the primary somatosensory cortex), and pyridoxal has been found in both fibers and cell bodies. Perikarya containing pyridoxal have been observed in the paraventricular hypothalamic nucleus, the periventricular hypothalamic region, and in the supraoptic nucleus. The fibers containing vitamins are thick, smooth (without varicosities), and are of medium length or long, whereas immunoreactive cell bodies containing vitamins are round or triangular. At present, there are insufficient data to elucidate the roles played by vitamins in the brain, but the anatomical distribution of these compounds in the monkey brain provides a general idea (although imprecise and requiring much more study) about the possible functional implications of these molecules. In this sense, here the possible functional roles played by vitamins are discussed