Showing papers on "Motor neuron published in 1973"

Intrasomatic Injection of Radioactive Precursors for Studying Transmitter Synthesis in Identified Neurons of Aplysia californica

Abstract: We introduced radioactive precursors directly into identified neurons of Aplysia californica. [3H]-Choline and L-[3H]tryptophan were injected with pressure into nerve cell bodies to study synthesis of acetylcholine and serotonin. We confirmed the cholinergic nature of R2, L10, and L11, identified neurons of the abdominal ganglion. Cells in the LD cluster (which contains motor neurons to the heart and gill) also converted most of the injected choline into acetylcholine. Neurons in the RB cluster (which contains an excitatory motor neuron to the heart) and the two metacerebral cells of the cerebral ganglion converted injected tryptophan to serotonin. No cell studied could convert both choline to acetylcholine and tryptophan to serotonin. Pressure permits rapid injection of precursors, from small amounts to amounts large enough to saturate intracellular synthetic pathways. In contrast to the results with injection, we found far less synthesis of acetylcholine and serotonin in identified nerve cell bodies when ganglia were incubated in the presence of the radioactive precursors.

Sporadic and familial parkinsonism and motor neuron disease.

Abstract: The ctincvrrence of two diseases raises the possibility .of a coninion etiology. Concurrent parkinsonism and motor neuron disease ( M N D ) are seen in several diseases including the S hy D r ager sy n d r o me J akob -Cr e u tz fe Id t d isease, a n d t h c pa r k i n so n ism d e in en ti a amyotrophic lateral sclerosis (ALS) coinplex of Guam. In these disorders the basal ganglia, corticospinal. and anterior horn cell signs are merely part o f a more encompassing disease. There also have been cases of either one o r both disorders occurring after encephalitis lethargica. In this paper MND refers to the broad group of motor neuron diseases; ALS refers specifically to the condition of patients with both upper and lower MND; and progressive spinal muscular atrophy (PSMA) refers t o the condition o f patients with only anterior horn cell signs o f the spinal cord. The postencephalitic parkinsonian syndrome is widely recognized and need not be discussed. Less well recognized are cases of MND alone ' -\" o r the combination o f MND and parkinsonism:,':l-'' developing after encephalitis lethargica. Reports of both syndromes occurring together in families o r sporadically without evidence o f previous encspha[itisL:3.I2 are still more scarce. We recently observed four patients with parkinsonism and ALS, none of whom had a history of encephalitis. Three had sporadic Neurology 1 Volume 23 /September I 9 73 990 disease while the fourth had a family history of spinocerebellar degeneration. All four cases c l e a r l y d i f f e r f r o m t h e w e l l k n o w n degenerative diseases mentioned above i n that there was n o dementia, orthostatic hypotension, o r other system degeneration.

Motor neuron disease with renal cell carcinoma and postoperative neurologic remission. A clinicopathologic report.

Abstract: H Nonmetastatic disease o f the nervous system associated with neoplasms has received increasing at tent ion s ince 1948, when DennyBrown' reported sensory neuropathy second a r y t o posterior r o o t ganglion degenerat ion in two patients with carcinoma o f the lung. Norris and Engel' in 1964 established an increased incidence of neoplasm in patients with m o t o r neuron d i sease , a n d subsequen t evidence f o r such an association has been presented by Brain, Croft and W i l k i n ~ o n . ~ T h e fol lowing case is presented as ano the r example o f this association, which is unusual in that the central nervous system process seems to have exacerbated initially a n d then remitted after surgical removal of a renal cell carcinoma.

Extension-sensitivity in the crayfish abdomen

Abstract: 1. In the isolated crayfish abdominal cord, the “spontaneous” discharge of postural motor neurons was found to depend (tonically) on cord length. This tonic cord stretch reflex inhibits flexor and excites extensor motor neurons and recruits additional extensor neurons. 2. The necessary and sufficient stimulus for the reflex in a particular ganglion is stretch of any part of the more posterior cord segments; stretch applied to anterior segments is without influence. 3. The reflex is present over the range of cord lengths obtaining in the intact animal. 4. The discharge rate of the tonic stretch receptor is shown to be also influenced. Evidence is presented that this is by way of the motor neuron which shares innervation of the superficial extensor musculature and the muscular part of the stretch receptor organ. 5. The existence of the tonic cord stretch reflex is taken as added evidence of the proprioceptive role of the cord stretch receptor system. The potential positive feedback nature of the reflex, its relation to other known proprioceptive reflexes, and its possible functional role are discussed.

Motor neuron loss due to aortic clamping in repair of coarctation.

Abstract: The caudal gray matter of t h e spinal cord has been shown in pathologic studies to be a locus of higlh vulnerability to hypotensive anoxia f rom cardiac arrest in children.’ Here we document the long-term clinical findings in a case of paraplegia subsequent to aortic clamping in repair of a preductal coarctation. The remarkably selective vulnerability of ventral spinal cord matter and motor neurons to ischemic anoxia is shown.

Motor neuron map of tropical cattle tick, Boophilus microplus (Canastrini) (Acarina : Ixodidae)☆

Abstract: The neurons in the brain are classified into 2 groups: the ganglionic neuron and the motor neuron A total of 153 motor neurons around the oesophagus in the center of the tick's brain was mapped Among these, cells 26, 27, 28, 29, 34, 35, 67, 68, 85, 86, 95, 96, 98, 102, 104, 106, 108, 124, 130, 92 and 109 are correlated with the movement of right fore leg, and cells 43, 42, 54, 53, 39, 40, 70, 48, 82, 84, 88, 107, 94, 105, 99, 103, 112, 125, 123 with the movement of left fore leg The first 19 neurons among the former group are symmetrical with their counterparts of the latter group except cells 92 and 109 which have no counterparts