Cytochemical localization of Na+/K+-ATPase activity in cochlear strial marginal cells after various catecholamine administrations

• Kanoh, N. ^[1] ; Dai, C.F. ^[2] ; Mohri, D. ^[1] ; Hori, S. ^[1]
  1. [1] Hyogo College of Medicine

     Hyogo College of Medicine

     Japón

     
  2. [2] Department of Otolaryngology, Eye Ear Nose and Throat Hospital, Shanghai Medical Univeristy, Shanghai, P.R. China
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 16, Nº. 4, 2001, págs. 1197-1201
• Idioma: inglés
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• Resumen

  • Sodium/potassium-activated adenosine triphosphatase (Na+/K+-ATPase) activity in the kidney and brain is high, and is regulated by catecholamines.

    Na+/K+-ATPase activity is also high in the basolateral infoldings of the strial marginal cells, where it aids in maintaining the characteristic electrolyte composition of the endolymph. To clarify the involvement of humoral control in strial function, particularly the role of catecholamines, the K+-dependent p-nitrophenylphosphatase (K+-NPPase) activity of strial marginal cells was investigated in guinea pigs using a ceriumbased cytochemical method. The effects of reserpine, serotonin (5-HT), norepinephrine (NE), epinephrine (EP), both alone and in combination, were studied. High doses of reserpine cause depletion of sympathetic substances. Stria1 K+-NPPase activity was decreased after reserpine or dopamine treatment, and was increased after 5-HT, NE, and EP treatment. After reserpinization, repeated treatment with 5-HT, NE, or EP led to detectable strial enzyme activity. Thus, exogenous 5-HT, NE, and EP were able to restore strial K+-NPPase activity in the reserpine-treated animals. These results suggested that biogenic amines regulate strial K+- NPPase activity. Thus, the function of the stria vascularis may be regulated by the opposing actions of these catecholamines, and 5-HT.