We studied five patients who received local injections of botulinum toxin for dystonic disorders to determine if there had been any distant effects on neuromuscular transmission. No patient developed weakness or abnormalities on routine electrophysiologic testing. In all patients who received more than 245 U of toxin, SFEMG in the extensor digitorum communis muscle, a muscle distant to all those injected, was abnormal. Fiber density was increased in the two patients who received the largest cumulative dose. Jitter was maximally increased at slow firing rates, confirming its presynaptic basis. Our results reveal that there is an effect on neuromuscular transmission in muscles distant to those injected with botulinum toxin for dystonia.

Aged↗

PubMedDate not supplied

Neurotensin interacts with dopaminergic neurons in rat brain.

Neurotensin (NT) injected intracerebroventricularly in rat increases dopamine (DA) turnover in the corpus striatum and nucleus accumbens. Significant increases in 3,4-dihydroxyphenylacetic acid (DOPAC) levels occurred within 15 minutes after injection with peak levels at 60 minutes. The effect on NT on DOPAC and homovanillic acid (HVA) accumulation was dose-dependent at 3-100 micrograms. NT, like haloperidol, stimulated 3,4-dihydroxyphenylalanine (DOPA) accumulation in striatal neurons, in the presence of DOPA decarboxylase inhibitor, after injection of gamma-butyrolactone (GBL). NT had a similar stimulatory effect on DOPA levels in the accumbens while haloperidol (0.25 mg.kg-1) had no significant effect in this brain region. NT did not block the inhibitory effect of apomorphine on DOPA accumulation in both the striatum and accumbens, while haloperidol inhibited apomorphine effect in both regions. NT also failed to displace 3H-spiperone from DA receptors and the presence of NT in the binding assay did not alter the ability of DA to displace 3H-spiperone in either brain region. These experiments demonstrate that NT increases DA turnover in both the nigrostriatal and mesolimbic pathways.

3,4-Dihydroxyphenylacetic Acid↗

PubMedDate not supplied

Receptor autoradiography of mu and delta opioid peptide receptors in spontaneously hypertensive rats.

The receptor autoradiographic distribution of opioid peptide receptors in spontaneously hypertensive rats (SHR) was compared to that of Sprague-Dawley (SD) rats, using the highly selective mu and delta opioid receptor ligands, [3H]DAGO (Tyr-D-Ala-Gly-NMe-Phe-Gly-ol) and [3H]DPDPE ([D-Pen2,D-Pen5]enkephalin), respectively. Although the distribution of these binding sites was similar in both strains, SHR showed significantly higher binding densities of mu receptors in 16 of 27 areas examined. These included the patch and matrix components of the caudate-putamen (CPu), olfactory tubercle, endopiriform nucleus, anterior cingulate cortex, ventral tegmental area lateroposteral thalamic nucleus and the ventral part of the dentate gyrus. In contrast, SHR had lower [3H]DAGO binding sites in the CA1 of the hippocampus. Conversely, SHR showed higher binding densities of delta receptors in 7 of 20 areas examined, including the CPu, CA2 and CA3 areas of the hippocampus and the central grey. High-to-low lateromedial gradients of striatal delta receptors were observed in both strains. Because opioid peptides are known to participate in locomotive behavior in rodents and in the control of blood pressure, the present results support a role of opioid peptidergic systems in the manifestation of hyperactivity and hypertension observed in SHR.

Animals↗

PubMedDate not supplied

Electromyographic findings in focal laryngeal dystonia (spastic dysphonia).

Spastic dysphonia is a clinical speech disorder characterized by spasms of the laryngeal muscles during phonation, producing a broken pattern of speech sometimes termed laryngeal stuttering. Fourteen patients with the diagnosis of spastic dysphonia based on voice quality were referred for evaluation; detailed clinical and electrophysiologic evaluations were performed. Laryngeal electromyographic (EMG) testing failed to demonstrate any spontaneous activity in the 14 patients tested. Seven patients (50%) had normal number and amplitude of motor unit potentials. Four of these had disparate amplitudes when compared with the other side, and two had complex motor unit potentials. The other seven patients (50%) had abnormal findings, including three patients with abnormally increased amplitude. Two patients had asynchronous activity characteristic of a tremor disorder. One patient had synchronous bursts of activity also affecting the diaphragm, later diagnosed as pyramidal and extrapyramidal disease. One patient had bursts of activity, and later presented with diffuse myoclonus. Laryngeal EMG therefore seemed to be a more precise way of evaluating patients presenting with a tremulous voice pattern termed spastic dysphonia. Clinical observation and EMG data demonstrated that spastic dysphonia is not a "spastic" disease. We identified patients with tremor (2), pyramidal and extrapyramidal disease (1), and myoclonic disorders (1). The remainder of the patients had clinical and EMG findings consistent with dystonia, a neurologic disorder characterized by abnormal, often action-induced, involuntary movements or uncontrolled spasms. We classify these patients as having "focal laryngeal dystonia" when the disorder occurs in isolation. It may also present as a component of a generalized dystonic syndrome.

Adult↗

PubMedDate not supplied

The genetics of idiopathic torsion dystonia.

The controversy regarding the mode of inheritance of idiopathic torsion dystonia in the Ashkenazi Jewish population has been resolved. At one time it was believed to be inherited as an autosomal recessive disorder. But recent studies, including a prospective, systematic, blinded analysis of the first- and second-degree relatives of 43 probands with age at onset less than 28 years found the disorder to be inherited in an autosomal dominant manner with a penetrance of approximately 0.30. Linkage analysis of Ashkenazi Jewish families with multiple affected members revealed that the gene for dystonia in this population is located in the q34 region of chromosome 9. This is the same region found to encode the dominant DYT1 gene for dystonia in a large non-Jewish family with a penetrance of about 0.70. It is likely that the disorder in these two ethnic populations may be caused by the same locus, and that the difference in penetrance may reflect different mutations operating in these two populations. We have found no evidence for genetic heterogeneity in the Ashkenazi Jewish families studied for linkage analysis, but there is at least one non-Jewish family with idiopathic torsion dystonia that is not linked to this region. Allelic association in 9q34 in the Ashkenazi Jewish population has narrowed the dystonia gene to a region of less than 2 cM.

Alleles↗