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PubMed2001

Long-term Medical Treatment for Parkinson's Disease.

The authors of this paper view Parkinson's disease (PD) as a clinically defined progressive syndrome of resting limb tremor, bradykinesia, muscle rigidity, and a shuffling unsteady gait that responds well to dopaminergic medications. Parkinson's disease is a not a single entity, but rather a syndrome with diverse causes, with both genetic and environmental risk factors. The clinician's concern is to rule out other entities, especially those having another specific treatment, and to give PD patients the best short- and long-term benefit, with the least possible unwanted side effects.

Journal Article↗
PubMed1981

Hypothyroidism presenting as muscle stiffness and pseudohypertrophy: Hoffmann's syndrome.

There is a spectrum of muscular abnormalities that occurs in patients with hypothyroidism. Alterations in deep tendon reflexes are commonly observed although more extensive muscle disease is less frequently seen. Two patients who demonstrated increased muscle mass, muscle stiffness with variable degrees of muscle weakness and low levels of serum thyroxine (Hoffmann's syndrome) are described. At the time of presentation, the serum creatinine phosphokinase level was more than 10 times greater than normal, and electromyography revealed repetitive positive waves. After therapy with thyroid hormone, there was complete resolution of the muscle abnormalities, and laboratory studies were performed. In this report, we review the clinical syndrome of muscle dysfunction that can be seen with the more severe forms of hypothyroid myopathy.

Female↗
PubMed1986

Exercise therapy for Parkinson's disease.

The outcomes of two different 12-week exercise programs were assessed by machine measurements of motor signs, tests of grip strength, motor coordination and speed, and neurophysiologic determinations of long-latency stretch responses in two groups of Parkinson patients matched for age, sex and stage of disease. The programs tested included an exercise program developed by the United Parkinson Foundation and a program of upper body karate training. Outcomes of these programs were similar. The majority of patients in both groups showed improvements in gait, tremor, grip strength and motor coordination on tasks requiring fine control. In one task involving whole body coordination there was a decline in function, while muscle rigidity was unchanged. The findings suggest that exercise is a useful adjunct to pharmacologic therapy.

Exercise Therapy↗
PubMed1990

Porcine stress syndrome: an animal model for the neuroleptic malignant syndrome?

The porcine stress syndrome is a genetic disorder of swine which, like neuroleptic malignant syndrome, is characterized by hyperthermia, muscle rigidity, and autonomic dysfunction. We investigated the porcine stress syndrome as a possible animal model for neuroleptic malignant syndrome in two ways. First, we administered haloperidol and lithium carbonate, alone and in combination, to susceptible and resistant swine. Second, we attempted to prevent the syndrome by pretreating animals with bromocriptine. Porcine stress syndrome was induced in 2 of 3 susceptible and 1 of 3 resistant swine by combined treatment with lithium and haloperidol, but was not triggered by treatment with lithium or haloperidol alone. Pretreatment with bromocriptine conferred no protection against the syndrome.

Animals↗
PubMed1988

Lactate dehydrogenase M-subunit deficiency: a new type of hereditary exertional myopathy.

Three families with a complete deficiency of the lactate dehydrogenase M subunit show exertional myoglobinuria. The response to ischemic forearm work is characteristic in these three families: an increase of venous lactate concentration after ischemic work was not observed and a marked increase of venous pyruvate was found. Glycolysis was markedly retarded in the patient's muscle in the glyceraldehyde 3-phosphate dehydrogenase (GA3PD) step. A significant increases in glyceraldehyde 3-phosphate, dihydroxyacetone phosphate and fructose 1,6-diphosphate were observed. The glycolysis retardation may be attributed to the impaired reoxidation of NADH produced by GA3PD action. The cytosolic fraction of skeletal muscle is rich in alpha-glycerophosphate dehydrogenase. This enzyme reoxidizes the excess NADH and drains triose phosphates from the glycolytic pathway under anaerobic conditions. For this reason, ATP production was significantly impaired and muscle cells were damaged in these patients. Consequently, the cytosolic enzymes and proteins such as creatine kinase and myoglobin were released into the blood stream. Otherwise, patients with a lactate dehydrogenase M-subunit deficiency do not show muscle stiffness and myoglobinuria under ordinary circumstances. They complain of muscle rigidity and sudden myoglobinuria after strenous exercise under anaerobic conditions. Thus, the lactate dehydrogenase M-subunit deficiency does not show any symptoms under ordinary circumstances, but is a latent hereditary disorder, now recognized as a new type of hereditary exertional myoglobinuria.

Adolescent↗
PubMed1993

Highly potent novel opioid receptor agonist in the 14-alkoxymetopon series.

The newly synthesized 14-alkoxymetopon derivatives, 14-methoxymetopon, 14-ethoxymetopon, 14-methoxy-5-methyl-morphinone, exhibit high affinity for the naloxone binding sites in rat brain. A substantial decrease in affinity was observed, in the presence of NaCl indicating a high degree of agonist activity. All three 14-alkoxymetopon derivatives displayed high affinity for [3H][D-Ala2,(Me)Phe4,Gly-ol5]enkephalin ([3H]DAMGO) binding sites, much less potency toward delta sites and were the least effective at kappa sites. Isolated tissue studies using the guinea pig ileum preparation confirmed their high agonist potency. Following administration the new compounds produced naloxone reversible antinociceptive effects and were 130-300 times more potent than morphine in the acetic acid induced abdominal constriction model in the mouse, and the hot plate and tail flick tests in the rat. The compounds also produced dose-dependent muscle rigidity, and potentiated barbiturate-induced narcosis. The in vivo apparent pA2 values for naloxone against 14-ethoxymetopon and morphine were similar in analgesia, suggesting an interaction with the same (mu) receptor site. The dependence liability of 14-alkoxymetopon derivatives in the withdrawal jumping test was less pronounced than that of morphine in either rats or mice, similar to tolerance to the their analgesic action. It is concluded that the 14-alkoxymetopon derivatives studied are selective and potent agonists at mu opioid receptors, with reduced dependence liability.

Analgesics↗
PubMed1983

Alterations in apomorphine concentration in spinal cord and brain follow the time course of catalepsies induced by different treatments.

Because evidence for the neurotransmitter role of dopamine in the gray matter of the spinal cord is accumulating, a question arises of whether or not spinal dopamine receptors are also involved in the effects of dopaminomimetics which are believed to induce beneficial effects in Parkinson's disease through an action thought to be mediated mainly by striatal dopamine receptors. To test this hypothesis muscimol and picrotoxin were injected unilaterally into the posterior part of the substantia nigra of rabbits permanently implanted with stainless-steel cannulae. Muscimol (a GABA-mimetic) enhanced locomotor activity, evoked a stereotyped behavior and contralateral rotations, and increased apomorphine-induced gnawing. Picrotoxin, a substance which inhibits GABA transmission, induced ipsilateral rotations, evoked catalepsy and muscle rigidity, and inhibited locomotor activity. Picrotoxin abolished apomorphine-induced gnawing, and increased haloperidol-mediated catalepsy. The catalepsy induced by an intranigral injection of picrotoxin, and the picrotoxin-evoked blockade of the apomorphine-induced gnawing disappeared within 16 h after the intranigral injection. Alterations in the apomorphine concentration in brain structures (n. caudatus and cerebral cortex) and in spinal cord after picrotoxin injection followed the same time course as the behavioral changes, and returned to the control values 16 h after injection of picrotoxin. Apomorphine was always injected 30 min before the rabbits were killed. Moreover, the substantial increase (to 300%) in apomorphine concentration in the spinal cord probably reflects the antagonism between behavioral changes induced by picrotoxin and the haloperidol catalepsy, rather than the decreased apomorphine concentrations observed in the brain structures. We suggest, therefore, that there exists a correlation between the behavioral effects, which are generally accepted as laboratory models of Parkinson's disease, and the enhanced apomorphine concentration in the spinal cord.

Animals↗
PubMed1992

Genetic differences in the development of physical dependence upon diazepam in Lewis and Fischer 344 inbred rat strains.

The purpose of the present study was to investigate physical dependence upon diazepam systematically in two inbred strains of rats, Lewis (LEW) and Fischer 344 (F344). Rats were chronically fed food containing diazepam on an escalating drug dosage schedule, from 1 and 2 to 12 mg/g of food, over a period of 30 days. During treatment, the growth curve in LEW and F344 rats was suppressed compared with the respective controls. Motor incoordination was evaluated by a rotarod performance test. The ranking of the motor incoordination during the final concentration of diazepam was as follows: F344 greater than LEW. After substitution of normal food for the diazepam-admixed food, various signs of diazepam withdrawal occurred 16-120 h later. These signs included vocalization, irritability, muscle rigidity, ear-twitching, Straub's tail, piloerection, fascicular twitch, tremor, convulsion, and death. The incidences of vocalization, ear-twitching, piloerection, and tremor in F344 were significantly higher than those in LEW rats. Furthermore, two of six F344 rats showed spontaneous convulsions and one rat died of convulsions. Overall withdrawal scores were significantly greater in F344 (16.0) than in LEW (6.3) rats. These results suggest that diazepam withdrawal severity is strongly influenced by genetic factors, and F344 rats are highly susceptible to dependence upon benzodiazepines.

Animals↗
PubMed1985

Thalamus as a relay station for catalepsy and rigidity.

The aim of the study was to determine to what extent catalepsy and tonic rigidity of muscles induced by muscimol administration into the ventral thalamic nuclei disturb the motor activity of rats. This study also aimed to test whether the ventromedial thalamic nucleus (Vm) was involved in transmitting effects evoked by the systemic injection of neuroleptics or opioids. For this purpose muscimol and/or picrotoxin was injected into the ventral thalamic nuclei and the behaviour of the animals was assessed in a series of test situations. It was found that muscimol administration to the Vm disturbs not only the initiation and performance of voluntary movements but also the occurrence of avoidance when the animal's life is endangered. Postural reflexes remained, however, undisturbed. Those effects seemed to be GABA- and site-specific to Vm. The haloperidol catalepsy was strongly inhibited by administration of picrotoxin to the Vm while the morphine catalepsy remained unchanged after picrotoxin. The Vm plays a crucial role in the motor behaviour and transmission of cataleptogenic effects of haloperidol, whereas similar effects produced by morphine appear to by-pass the investigated thalamic region.

Animals↗
PubMed1987

Time-dependent effects of papaverine on electrically induced seizures in rats.

We tested the effects of papaverine, an adenosine uptake blocker, on hippocampal-elicited afterdischarges in rats. Rats were injected with 35 mg/kg papaverine and tested for seizure responses at 5, 20, and 60 min postinjection. Papaverine produced a potent inhibition of afterdischarge generation, greatly reduced afterdischarge duration, and blocked hippocampal-kindled seizures. This anticonvulsant effect was greatest 5 min postinjection and had largely dissipated by 60 min. Because papaverine also produced a Parkinson-like syndrome involving muscle rigidity, these results are discussed in terms of effects on dopamine and adenosine systems.

Adenosine↗
PubMed1981

Effect of ATP concentration and pH on rigor tension development and dissociation of rigor complex in glycerinated rabbit psoas muscle fiber.

Isometric rigor tension development of glycerinated rabbit psoas muscle fibers in a medium, due to the formation of rigor complexes, was estimated at varying ATP concentrations from 0 to 2.5 mM and pH values from 6.75 to 8.20. The dissociation of rigor complexes was also estimated under the same conditions. When muscle fibers developed rigor tension from the relaxed and rigor states, the magnitude of rigor tension increased with increasing concentration of ATP. Transition between rigor and relaxation in single fibers occurred discontinuously at constant levels (critical levels) of ATP which were determined by pH. The critical concentrations of ATP necessary for inducing the transitions between rigor and relaxed states were also increased exponentially with increased pH. Incomplete repetition of tension development by the same fiber was also observed. This incomplete reversibility was divided into two types: one which showed a decay in rigor tension and another which showed no decay. The reason for the incomplete reversibility was discussed

Adenosine Triphosphate↗
PubMed1986

Distinct sites of functional interaction between dopamine, acetylcholine and gamma-aminobutyrate within the neostriatum: an electromyographic study in rats.

In order to study the functional interaction between dopamine, acetylcholine and gamma-aminobutyrate within the rat neostriatum, we investigated the effect of intrastriatal injection of different drugs acting on these transmitter systems on muscle tone measured as tonic activity in the electromyogram of the gastrocnemius muscle. Bilateral injection of haloperidol (500 ng) into the rostral neostriatum (rostral injection: A8920-9650(46] induced tonic activity in the electromyogram, whereas injection into the intermediate part (intermediate injection; A7020-7890(46] was ineffective. Muscimol (25 ng) induced tonic activity in the electromyogram, when injected into the intermediate part and not into the rostral part, while bethanechol (1 microgram) was effective when injected into either site. Haloperidol-induced tonic activity in the electromyogram was prevented by coadministration of apomorphine (500 ng) or scopolamine (1 microgram), but not of bicuculline (300 ng). Haloperidol-induced tonic activity in the electromyogram was also reduced by subsequent intermediate injection of scopolamine or bicuculline, while apomorphine was ineffective. Tonic activity in the electromyogram induced by rostral injection of bethanechol was prevented by coadministration of scopolamine, but not of apomorphine. Intermediate injection of scopolamine or bicuculline reduced the tonic activity in the electromyogram after rostral or intermediate injection of bethanechol. Tonic activity in the electromyogram induced by intermediate injection of muscimol was prevented by coadministration of bicuculline, but not of scopolamine. Rostral injection of apomorphine or scopolamine failed to alter the tonic activity in the electromyogram induced by intermediate injection of bethanechol or muscimol. These results point to the existence of: a functional interaction between dopamine and acetylcholine in the rostral neostriatum; a functional interaction between acetylcholine and gamma-aminobutyrate in the intermediate neostriatum, and a functional flow of information from the rostral to the intermediate neostriatum.

Acetylcholine↗