EXPERIMENTAL OBSERVATION ON THE ACTION POTENTIAL OF THE LABYRINTHIN NYSTAGMUS. IST REPORT. ACTION POTENTIALS OF THE OCULAR MUSCLE OF THE RABBIT
スポンサーリンク
概要
- 論文の詳細を見る
Ocular muscles of the rabbit, were detached from the insertion by Topolansky-Bartels' procedure and connected via injection nedle electrodes and amplifier to an oscillograph of N-3 type. The contraction and relaxation of the muscle was converted to the change of electric resistance so that the myographical record could be obtained by an electrical way. The résumé of the results so far obtained follows:<BR>(1) The stroke of nystagmus movement is a tetanus in nature instead of a single twitch. The turning point from the slow phase to the quick phase is distinct in the records both of the agonist and the antagonist muscles, while the quick phase goes gradually over into the following slow phase, so that it is difficult in the action potential record to set a reparating landmark between the two phases. At the former turning point there is found between the agonist and muscles antagonist a time shift about a millisecond.<BR>(2) In normal rabbits, it is difficult to determine the frequency of the action potential numerically, since the main and accessory waves appear intermingled with each other, inspite of the extremely short interpolar distance between the electrodes we used, and the main wave is of a variable size.<BR>(3) Resting ocular muscles also develop action potential. Whether this muscular tonus is wholely of labyrinthine nature or not is a problem still to be solved.<BR>(4) By adjusting the labyrinthine stimulation, the frequency and amplitude of the nystagmus could be changed at will. In cases of augumented amplitude, the action potential recond reveals increase in the twitch frequency of each muscle fibre and in the number of active fibres. In such cases it is natural to assume that it is caused by an inerease of the discharge frequency from each nerve cell in the centre and increased number of neurons involved. Increase in nystagmus frequency is accompanied by diminution of the amplitude even to the degree that the nystagmus movement is no more visible on the myogram, although there is still discernible-some characteristic behaviour of the muscles in the action potential. The agonist muscle, namely, is in a continued, almost maximal contraction, while the antagonist muscle shows an action potential akin to that of a single twitch. On a further enhancement of labyrinthine excitation, the antagonist muscle remains in a completely relaxed state, no action potential being discernible.<BR>(5) Effect of ether anaesthesia on the nystagmus, caused by unilateral destruction of the labyrinth, consists in a lowered frequency of the impulse discharge on the part of each neuron, decreased number of neurons in action, and disturbance of the reciprocal innervation, which mechanism may disappear in the end.
- 社団法人 日本耳鼻咽喉科学会の論文