Effects of calcium and potassium channel blockers on changes in transepithelial potential and spike responses in Lorenzi ampullary electroreceptors in Raja clavata

Broun, G. R.; Govardovskii, V. I.; Cherepnov, V. L.

doi:10.1007/bf01052184

Cited by 2 publications

(4 citation statements)

References 6 publications

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“…The presence of K channels in basal membranes of the ampullary epithelium was reported previously (Clusin and Bennett, 1979a,b;Broun et al, 1984). In addition to Cl(Ca) channels, K channels could also generate a positive conductance in basal membranes of the electroreceptive epithelium.…”

Section: K Channels In Basal Membranessupporting

confidence: 74%

Ion channels and transporters in the electroreceptive ampullary epithelium from skates

Fishman

1995

Biophysical Journal

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Two ampullary epithelial properties necessary for electroreception were used to identify the types of ion channels and transporters found in apical and basal membranes of ampullary receptor cells of skates and to assess their individual role under voltage-clamp conditions. The two essential properties are (1) a steady-state negative conductance generated in apical membranes and (2) a small, spontaneous current oscillation originating in basal membranes (Lu and Fishman, 1995). The effects of pharmacological agents and ion substitutions on these properties were evaluated from transorgan or transepithelial complex admittance determinations in the frequency range 0.125 to 50 Hz measured in individual, isolated ampullary organs. In apical membranes, L-type Ca channels were found to be responsible for generation of the steady-state negative conductance. In basal membranes, K and Ca-dependent Cl (Cl(Ca)) channels were demonstrated to contribute to a net positive membrane conductance. L-type Ca channels were also evident in basal membranes and are thought to function in synaptic transmission from the electroreceptive epithelium to the primary afferent nerve. In addition to ion channels in basal membranes, two transporters (Na+/K+ pump and Na(+)-Ca+ exchanger) were apparent. Rapid (minutes) cessation of the current oscillation after blockage of any of the basal ion channels (Ca, Cl(Ca), K) suggests critical involvement of each of these channel types in the generation of the oscillation. Suppression of either Na+/K+ transport or Na(+)-Ca2+ exchange also eliminated the oscillation but at a slower rate, indicating an indirect effect.

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Section: K Channels In Basal Membranessupporting

confidence: 74%

Ion channels and transporters in the electroreceptive ampullary epithelium from skates

Fishman

1995

Biophysical Journal

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“…The anodal stimulus, in contrast, hyperpolarizes the apical membrane and closes Ca channels, thus decreasing the inward current through this face, which leads to the hyperpolarization of the basal face and reduced secretion of the transmitter. According to another hypothesis (Brown and Govardovsky 1983 a, b;Brown and Ilyinsky 1984), the unusual response of the Lorenzinian ampullae in elasmobranchs to the polarity of electric stimulation, i.e., an increase of the afferent discharge by lumen-negative stimuli which hyperpolarizes the presynaptic membrane of the receptor cell, is not linked with the spontaneous activity of the .,.…”

Section: J\mentioning

confidence: 96%

“…As in the case of other synapses there is every reason to assume that the basal membrane of the receptor cell has potentialdependent calcium channels which trigger transmitter release processes. Indeed, the experiments on the ampullae of Lorenzini in the marine catfish demonstrated the existence of oscillatory responses of receptor cells, which were blocked by perfusing the basal membrane with tetraethylammonium (TEA) and 4-aminopyridine (4-AP) Brown et al 1985). These responses were also blocked by Co2+ and Cd 2 +.…”

Section: The Effect Of Ions On Synaptic Processesmentioning

confidence: 97%

“…The number of receptor cells in the receptor organs varies strongly, from 1 -4 in weakly electric species to several thousands in marine fish. The structural fea-tures of ampullary receptors and their functional properties are treated in more detail in a number of basic studies and reviews (Szabo 1965(Szabo , 1974Waltman 1966;Andrianov et al 1979;Andrianov and Ilyinsky 1983;Brown and Ilyinsky 1984;Zakon 1986). Tuberous receptors are also located in epidermal capsules; however, the receptor cells have no direct contact with the outer medium since the external accessory cells extend between the sensory cells and the epidermal surface.…”

Section: Anatomy Of the Receptor Systemsmentioning

confidence: 98%

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Synaptic Transmission in the Mechano- and Electroreceptors of the Acousticolateral System

Akoev

Andrianov

1989

Progress in Sensory Physiology 9

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Effects of calcium and potassium channel blockers on changes in transepithelial potential and spike responses in Lorenzi ampullary electroreceptors in Raja clavata

Cited by 2 publications

References 6 publications

Ion channels and transporters in the electroreceptive ampullary epithelium from skates

Ion channels and transporters in the electroreceptive ampullary epithelium from skates

Synaptic Transmission in the Mechano- and Electroreceptors of the Acousticolateral System

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