Immunologic study of vinculin in Duchenne muscular dystrophy.

Using immunologic techniques, we studied vinculin, a cytoskeletal protein associated with the membrane-skeleton of the muscle fiber. We examined muscle biopsies from five patients with Duchenne muscular dystrophy (DMD), two with Becker's muscular dystrophy (BMD), three normal human muscle samples, and four biopsies from disease control patients. All DMD patients showed patchy and low-intensity immunostain at the sarcolemma of most fibers and, by immunoblot analysis, the content of vinculin was 42 to 61% of control values. There was no significant vinculin deficiency in samples from patients with BMD and other disease controls. The data suggest that vinculin content is reduced only in muscle where dystrophin is absent or sparse.     

Involvement of NMDA and NonNMDA Receptors in Motor Task--related Activity in the Primary and Secondary Cortical Motor Areas of the Monkey

The involvement of the NMDA and non-NMDA receptors in the task-relatedneuronal activity of the primary motor cortex (MI), premotorcortex (PM), supplementary motor area (SMA), and an area rostralto the SMA (pre-SMA) of two monkeys (Macace fuscata) was examinedduring performance of a trained motor task. The selective NMDAantagonist 0-2-amino-5-phosphonovaleric acid (APV) and the non-NMDAantagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) wereiontophoretically applied to motor task-related neurons. A totalof 568 task-related neurons (435 movement related, 83 set related,50 mixed type) were recorded from the MI, PM, SMA, and pre-SMA,and the effects of APV and CNQX were examined in the individualneurons. In many neurons, APV selectively or preferentiallysuppressed the spontaneous discharge rather than movement-relatedactivity. In many neurons, the movement-related activity wasmore selectively or effectively suppressed by CNQX than by APV.However, the set-related activity was affected by both APV endCNQX. The neurons in layers I and II were affected more stronglyby APV end CNQX than those in layers V and VI. No correlationwas found between the magnitude of task-related activity inthe control (no drug application) period and the effectivenessof APV or CNOX. These results indicate that both NMDA and non-NMDAglutamate receptors are involved in motor task-related neuronalactivity of both primary and secondary motor areas, althoughthe contribution of these two receptors to individual neuronalactivity varies a great deal.     

Sequential changes of [H]forskolin, [H]cyclohexyladenosine and [H]PN200-110 binding sites in the brain of 6-hydroxydopamine-lesioned rats

Receptor autoradiographic technique was studied to investigate sequential changes in adenylyl cyclase, adenosine A1 receptors and L-type calcium channels in the striatum and substantia nigra 1-8 weeks after unilateral 6-hydroxydopamine injection of the medial forebrain bundle in rats. [3H]Forskolin, [3H]cyclohexyladenosine (CHA) and [3H]PN200-110 were used to label adenylyl cyclase, adenosine A1 receptors and L-type calcium channels, respectively. The degeneration of the nigrostriatal pathway caused a significant increase in [3H]forskolin binding in the striatum of both the ipsilateral and contralateral sides from 2 to 4 weeks post-lesion. The ipsilateral substantia nigra showed a transient increase in [3H]forskolin binding 4 weeks post-lesion. In contrast, [3H]CHA binding showed no significant change in most brain areas after lesioning. On the other hand, a conspicuous decrease in [3H]PN200-110 binding was observed in the dorsolateral striatum of ipsilateral side 4 weeks post-lesion. Thereafter, the striatum of both the ipsilateral and contralateral sides showed a significant decrease in [3H]PN200-110 binding 8 weeks post-lesion. These results demonstrate that unilateral 6-hydroxydopamine into the medial forebrain bundle of rats can experimentally cause a significant increase in adenylyl cyclase binding sites in the striatum and substantia nigra, whereas no conspicuous change in adenosine A1 receptors is observed in these areas during post-lesion. In contrast, L-type calcium channels were progressively damaged in the striatum after unilateral 6-hydroxydopamine treatment. These findings suggest that adenylyl cyclase and calcium system may contribute to the degeneration processes of the dopaminergic neurones.     

Cellular activity in the supplementary eye field during sequential performance of multiple saccades

To investigate how single neurons in the supplementary eye field (SEF) participate in sequential performance of multiple saccades, we analyzed presaccadic activity while monkeys were performing three saccades in six different orders from memory. The saccades in each sequence were separated by a fixation period and initiated from the same fixation point with intervening return saccades. We found that the majority of the presaccadic activity of the SEF neurons differed significantly depending on the numerical position of saccades in each sequence (rank order). This rank-order selectivity was found in parallel with the selectivity for the sequence of three saccades. Our data suggest a role for SEF neurons in the coding of temporally ordered saccadic eye movements.     

Neurons in the rostral cingulate motor area monitor multiple phases of visuomotor behavior with modest parametric selectivity

We examined the cellular activity in the rostral cingulate motor area (CMAr) with respect to multiple behavioral factors that ranged from the retrieval and processing of associative visual signals to the planning and execution of instructed actions. We analyzed the neuronal activity in monkeys while they performed a behavioral task in which 2 visual instruction cues were given successively with an intervening delay. One cue instructed the location of the target to be reached; the other cue instructed which arm was to be used. After a second delay, the monkey received a motor-set cue to be prepared to initiate the motor task in accordance with instructions. Finally, after a GO signal, the monkey reached for the instructed target with the instructed arm. We found that the activity of neurons in the CMAr changed profoundly throughout the behavioral task, which suggested that the CMAr participated in each of the behavioral processing steps. However, the neuronal activity was only modestly selective for the spatial location of the visual signal. We also found that selectivity for the instructional information delivered with the signals (target location and arm use) was modest. Furthermore, during the motor-set and movement periods, few CMAr neurons exhibited selectivity for such motor parameters as the location of the target or the arm to be used. The abundance and robustness of the neuronal activity within the CMAr that reflected each step of the behavioral task and the modest selectivity of the same cells for sensorimotor parameters are strikingly different from the preponderance of selectivity that we have observed in other frontal areas. Based on these results, we propose that the CMAr participates in monitoring individual behavioral events to keep track of the progress of required behavioral tasks. On the other hand, CMAr activity during motor planning may reflect the emergence of a general intention for action.