The innervation of the cranial vessels by the trigeminal nerve, the trigeminovascular system, has recently been the subject of study in view of its possible role in the mediation of some aspects of migraine. Since stimulation of the trigeminal ganglion in humans leads to facial pain and flushing and associated release of powerful neuropeptide vasodilator substances, their local release into the extracerebral circulation of humans was determined in patients who had either common or classic migraine. Venous blood was sampled from both the external jugular and cubital fossa ipsilateral to the side of headache. Plasma levels of neuropeptide Y, vasoactive intestinal polypeptide, substance P, and calcitonin gene-related peptide were determined using sensitive radioimmunoassays for each peptide, and values for the cubital fossa and external jugular and a control population were compared. A substantial elevation of the calcitonin gene-related peptide level in the external jugular but not the cubital fossa blood was seen in both classic and common migraine. The increase seen in classic migraine was greater than that seen with common migraine. The other peptides measured were unaltered. This finding may have importance in the pathophysiology of migraine.

The trigeminal ganglion was activated, in humans by thermocoagulation as part of the treatment of trigeminal neuralgia and in cats by electrical stimulation, and blood samples were taken from the external jugular vein for estimates of plasma levels of substance P and calcitonin gene-related peptide (CGRP). In those patients who were noted at the time of coagulation to have flushed there were marked elevations of the local (cranial) levels of both peptides. However, in the nonflushing patients no changes in the peptide levels were observed. Parallel experiments in the cat revealed that the levels of substance P-like and CGRP-like immunoreactivity were increased during electrical stimulation of the trigeminal ganglion. The observation of elevation of substance P-like and CGRP-like immunoreactivity after activation of the nociceptive afferent system of the head provides new insights into a putative role of peptides in the pathophysiology of migraine and cluster headache, and suggests new areas of possible therapeutic intervention.

A simple reversed-phase nano-column purification and sample preparation technique is described, which markedly improves the mass spectrometric analysis of complex and contaminated peptide mixtures by matrix-assisted laser desorption/ionization (MALDI). The method is simple, fast and utilizes only low-cost disposables. After loading the sample on the column and a subsequent washing step, the analyte molecules are eluted with 50-100 nl of matrix solution directly on to the MALDI/MS target. The washing step ensures removal of a wide range of contaminants. The small bed volume of the column allows efficient sample concentration and the elution process yields very small sample spots. This simplifies the analysis and minimizes discrimination effects due to sample heterogeneity, because the desorption/ionization laser simultaneously irradiates a large portion of the sample. Taken together, these features of the method significantly improve the sensitivity for MALDI/MS analysis of contaminated peptide samples compared with the commonly used sample preparation procedures. This is demonstrated with in-gel tryptic digests of proteins from human brain that were separated by 2D gel electrophoresis. Furthermore, it is shown that with this method 2,5-dihydroxybenzoic acid (DHB) acts as an efficient matrix for peptide mapping. Both detection sensitivity and sequence coverage are comparable to those obtained with the currently preferred matrix alpha-cyano-4-hydroxycinnamic acid (CHCA). The higher stability of peptide ions generated with DHB compared with CHCA is advantageous when analyzing fragile sample molecules. Therefore, the method described here is also of interest for the use of Fourier transform ion cyclotron resonance (FT-ICR) or ion-trap mass analyzers.

Evidence has been obtained that catecholamines and their metabolites are present in single lymphocytes and extracts of T-and B-ceUl clones by use of capiUlary electrophoresis with electrochemical detection. Pharmacological inhibition of tyrosine hydroxylase reduces observed catecholamine levels, suggesting catecholamine synthesis by lymphocytes. Intracelular dopamine levels are shown to be increased by extracellular dopamine, suggesting a cellular-uptake mechanism. Furthermore, incubation with either dopamine or L-dihydroxyphenylalanine, a precursor of dopamine, results in a dosedependent inhibition of lymphocyte proliferation and differentiation. Together, these results suggest the presence of an autocrine loop whereby lymphocytes down-regulate their own activity.

No abstract

No abstract

Background and aims: Stress often worsens the symptoms of irritable bowel syndrome (IBS). We hypothesised that this might be explained by altered neuroendocrine and visceral sensory responses to stress in IBS patients. Subjects and methods: Eighteen IBS patients and 22 control subjects were assessed using rectal balloon distensions before, during, and after mental stress. Ten controls and nine patients were studied in supplementary sessions. Rectal sensitivity (thresholds and intensity-visual analogue scale (VAS)) and perceived stress and arousal (VAS) were determined. Plasma levels of corticotropin releasing factor (CRF), adrenocorticotropic hormone (ACTH), cortisol, noradrenaline, and adrenaline were analysed at baseline, immediately after stress, and after the last distension. Heart rate was recorded continuously. Results: Thresholds were increased during stress in control subjects (p,0.01) but not in IBS patients. Both groups showed lower thresholds after stress (p,0.05). Repeated distensions without stress did not affect thresholds. Both groups showed increased heart rate (p,0.001) and VAS ratings for stress and arousal (p,0.05) during stress. Patients demonstrated higher ratings for stress but lower for arousal than controls. Basal CRF levels were lower in patients (p,0.05) and increased significantly during stress in patients (p,0.01) but not in controls. Patients also responded with higher levels of ACTH during stress (p,0.05) and had higher basal levels of noradrenaline than controls (p,0.01). Controls, but not patients, showed increased levels of adrenaline and noradrenaline in response to stress (p,0.05). Conclusions: Stress induced exaggeration of the neuroendocrine response and visceral perceptual alterations during and after stress may explain some of the stress related gastrointestinal symptoms in IBS.

SUMMARYThe immune and the nervous systems are anatomically closely related and interact with each other by molecules common to both systems, such as cytokines and neurotransmitters. The purpose of this study was to investigate the participation of catecholamines in the neuroimmunological network. The ability of immune cells to produce catecholamines was examined by a highly sensitive capillary electrophoresis assay, which permits detection of easily oxidized catecholamines in the zeptomole (10 ÿ 21 ) range. In addition, the effects of catecholamines on in vitro proliferation, differentiation and apoptosis of lymphocytes were assessed. Mouse spleen cells and macrophages contained on average 7 2 10 ÿ 17 and 2 2 10 ÿ 17 mole dopamine per cell, respectively. In the former cell population also norepinephrine was found. Several mouse B-and T-cell hybridomas were also shown to contain endogenously produced dopamine in levels ranging from 7 2 10 ÿ 20 to 2 2 10 ÿ 18 mole dopamine per cell. In addition, one of the T-cell hybridomas proved to synthesize norepinephrine. The dopamine production of lymphocytes was blocked by the tyrosine hydroxylase inhibitor a -methyl-p-tyrosine, whereas incubation with the precursor L-DOPA increased the dopamine content. Incubation with L-DOPA, dopamine and norepinephrine dose-dependently suppressed mitogen induced proliferation and differentiation of mouse lymphocytes. Even short-time pretreatment of lymphocytes with L-DOPA and dopamine strongly suppressed lymphocyte proliferation and cytokine production. Incubation of lymphoid cells with L-DOPA, dopamine and norepinephrine dose-dependently induced apoptosis which, at least partly, explains the suppressive effects of catecholamines on lymphocyte function. Our results demonstrate that catecholamines: (i) are actively produced by lymphocytes and (ii) have the capacity to act as auto-and/or paracrine regulators of lymphocyte activity through induction of apoptosis.