Cytochemical localization of adenylyl cyclase activity within the sensory epithelium of the trout saccule

Marian J. Drescher*, Robert C. Kern, James S. Hatfield, Dennis G. Drescher

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Adenylyl cyclase, the enzyme of synthesis of cAMP, the second messenger molecule mediating signal transduction in response to sensory, neurotransmitter and hormonal stimuli, has been localized in the sensory epithelium of the rainbow trout (Salmo gairdneri R.) saccule by cytochemical detection of enzyme activity. In the sensory receptor cell, or hair cell, reaction product has been visualized in the stereocilia in close association with the outer cell membrane and also at the apical surface of the cuticular plate. A diffuse distribution of precipitate was observed within the cytoplasm of terminal endings of nerve fibers presumed to be efferent on the basis of characteristic synaptic specializations including presynaptic vesicles and a postsynaptic cistern lying within the hair cell. Occasionally, reaction product was observed to be associated with the external cell membrane of these nerve terminals. There appeared to be little or no adenylyl cyclase activity associated with the plasma membrane at the base of the hair cell or in presumptive afferent nerve endings. However, a subpopulation of nerve fiber endings which exhibited both efferent and afferent synaptic specializations contained precipitate. A concentration of adenylyl cyclase activity in hair cell stereocilia and efferent nerve terminals in the sensory epithelium is suggestive of a role for cAMP in second messenger action at these sites, possibly related to mechanosensory transduction and efferent neuromodulation, respectively.

Original languageEnglish (US)
Pages (from-to)145-148
Number of pages4
JournalNeuroscience Letters
Issue number2
StatePublished - Aug 25 1995


  • Adenylyl cyclase
  • Cytochemistry
  • Efferent endings
  • Hair cell
  • Saccular macula
  • Salmo gairdneri R.

ASJC Scopus subject areas

  • Neuroscience(all)


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