Objectives: To determine the prevalence of Thai demyelinating diseases regarding demographic data, symptoms and signs, associated diseases, disease progression, cerebrospinal fluid analysis and imaging findings. Methods: A multicenter retrospective study of 107 MS patients attending the Neurological Centers in Thailand during June and December 2004 was performed. Each had an initial diagnosis of demyelinating diseases. Results: From 107 patients, there were 78.5% female and 21.5% male with the female: male ratio of 3.7:1. The age at onset was 32.7±11.5 years. The mean disease duration was 3.8±5.1 years and the mean number of relapses was 4.6±4.4 with annual relapse rate of 1.5±1.3 times. None reported a family history of MS. Recurrent optico-spinal form was 27.1% followed by 17.8% of spinal form and 15% of western form of MS. The most common presenting symptom was visual impairment (51.4%). Only 24.1% demonstrated oligoclonal bands in CSF. The median score of EDSS at their latest visits was 3.0 with mean score of 3.8±3.0. Conclusions: MS in Thailand is different from Western countries. There were no occurrence of MS in families, higher incidence of visual impairment at onset, more common recurrent optico-spinal form and lower incidence of oligoclonal bands in the CSF.

Objectives: Calcitonin gene-related peptide (CGRP) is currently considered to be a major contributing factor in migraine headache. Botulinum toxin type A (BTXA) was found to be effective in migraine prevention. However, the mechanism of action in patients was unknown. Using injection as in clinical setting, the study aimed to determine whether BTXA could decrease the sensitization of the trigeminovascular nociceptive system through the reduction of CGRP action. Methods: Adult male Wistar rats were pretreated with normal saline solution or BTXA before KCl application to induce cortical spreading depression (CSD) or NaCl application as a control. Regional cerebral blood flow at parietal cortex was measured for 90 min after KCl or NaCl application. Tissues from trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC) were then collected for CGRP and c-Fos measurement respectively. Results: BTXA pretreatment significantly decreased the cumulative blood flow and number of hyperemic peaks induced by KCl. Numbers of CGRP positive cells at TG and c-Fos positive cells at TNC were also reduced by BTXA.Conclusion: BTXA pretreatment reduced CGRP production and release from the TG leading to lessen CSD production and persistent activation of TNC which played a major role in migraine headache.