Electrical responses of the smooth muscle of the guinea-pig cerebral artery to brief electrical stimulation
| Autor: | Ken Hotta, Yoshimichi Yamamoto |
|---|---|
| Rok vydání: | 1986 |
| Předmět: |
Atropine
Guanethidine Physiology Guinea Pigs Cerebral arteries Stimulation Tetrodotoxin Stimulus (physiology) Ion Channels Muscle Smooth Vascular Membrane Potentials medicine Animals Spike potential Electromyography Chemistry Depolarization General Medicine Cerebral Arteries Electric Stimulation Electrophysiology Cerebrovascular Circulation Anesthesia Biophysics Calcium medicine.symptom medicine.drug Muscle contraction |
| Zdroj: | The Japanese Journal of Physiology. 36:77-90 |
| ISSN: | 1881-1396 0021-521X |
| DOI: | 10.2170/jjphysiol.36.77 |
| Popis: | Electrical responses to brief electrical stimulation were investigated in the cerebral artery of a guinea-pig using a microelectrode. A single brief stimulus (0.05 ms) induced a spike potential followed by a depolarizing slow-potential, and these events were associated with muscle contraction. An outward current injected into the smooth muscle cell induced spike potential but failed to induce depolarizing slow-potential. These activities persisted in the presence of TTX (10(-6) M), guanethidine (5 X 10(-6) M), or atropin (10(-5) M). TEA (5 mM) enhanced the amplitude of the spike potential, but not that of the depolarizing slow-potential. When the external Na was reduced, the membrane transiently hyperpolarized. During this period, the depolarizing slow-potential could be evoked. In a Cl-deficient solution, the membrane depolarized and the amplitude of the depolarizing slow-potential decreased. From these observations it is believed that the contribution of K, Na, or Cl is minor. In a 20 mM-Ca solution, a brief stimulation induced neither spike potential nor depolarizing slow-potential, but did induce a hyperpolarizing slow-potential. The hyperpolarizing slow-potential was also induced in a Na-deficient solution, but only after completion of Na re-distribution across the membrane. These observations suggest that a substance released by brief stimulation produces a prolonged change in ionic conductances of the smooth muscle membrane, allowing the muscle to contract for a certain period. |
| Databáze: | OpenAIRE |
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