Electrophysiological and Morphological Studies of SOD1 Transgenic Mice: An Animal Model of ALS

Amyotrophic lateral sclerosis (ALS) is a disease where upper and lower motor neurons die, and it is often associated with mutations of superoxide dismutase 1 (SOD1). We have used mouse models to compare physiologic and morphologic characteristics of cervical motor neurons in wild-type and mutant animals. Slices of the cervical spinal cord were prepared from old wild-type and mutant G93A and G85R mice, and intracellular recordings of membrane potential, resistance and responses to application of excitatory neurotransmitters were studied. Some motor neurons were injected with Lucifer Yellow for morphological analysis. There were no significant differences between membrane potential in the SOD1 mutants and aged wild-type mice, but membrane resistance was somewhat higher in the mutant motor neurons. Dendrites of the mutant motor neurons were not responsive to ionophoretic application of excitatory amino acids, although the cell body responded strongly. In Lucifer-filled cells, the dendrites were found to disappear. Mutant motor neurons were sometimes spontaneously active. Responses of mutant motor neurons to perfused glutamate with varying calcium concentrations in the Ringer’s solution were different from those of the wild-type cells.

Physiological and Pharmacological Studies on Cervical Motor Neurons in Slices Prepared from Neonatal and Aged Mice

The effects of age on the physiological properties of cervical motor neurons were examined in slices made from an excised spinal cord graft of ICR mice from the second day after birth to age 350 days. The membrane potential of post-natal day 2 (PD2) to PD350 was about -65 mV and did not change greatly with age, although it was slightly higher at PD2. However, there were significant changes in membrane resistance, which increased with age from about 15 to 30 MΩ. The depolarization induced by the excitatory amino acid agonists, kainic acid, NMDA and AMPA, decreased with aging in spite of the increase in membrane resistance. The motor neurons of the aged mice showed delayed recovery from excitation caused by excitatory amino acid agonists. By injecting Lucifer yellow CH into motor neurons, it was observed that the dendrite trees become thin, and some of the dendrite branches were missing in older animals.

Spinal Cord Compression Due to Hypertrophic Dorsal Pachymeningitis in a Patient with ANCA + Vasculitis

Hypertrophic pachymeningitis is an infrequent cause of spinal cord compression, secondary to an intracanal and extramedullary inflammatory infiltrate in patients with Wegener’s disease, and it produces canal stenosis and spinal cord compression. We present the case of a patient with this rare entity, providing explanatory images, who was treated with corticosteroids with partial remission of the lesions.