[Effect of calcium ions on the electrical and temperature sensitivity of the ampullae of Lorenzini of Black Sea skates].

Changes in the ambient calcium concentration affected similarly both thermal and electrical sensitivity of electroreceptors of the Lorenzini ampullae in the skates. In Ca-free solution containing EGTA the sensitivity first decreased, then increased and after that blocking of synaptic transmission occurred. In Ca-rich solution both thermal and electrical sensitivity decreased.

[Analysis of the mechanism of amplitude change in Pacinian corpuscle receptor potential in a solution with a decreased calcium ion concentration].

The effect of Ca2+-free solution on the amplitude increase in the receptor potential (RP) of Pacinian corpuscles was studied using external perfusion technique. The RP amplitude increased in Ca2+-free solution. It was blocked after addition of 10-20 mM of tetraethylamonium.

[Analysis of the mechanism of perception of temperature stimuli by the ampullae of Lorenzini of Black Sea skates].

The single nerve fibre responses of the Lorenzini ampulla to thermal stimulation were studied in the Black Sea skates, Trygon pastinaca, and Raja clavata. Cooling of sea water applied to the ampulla capsule or to the skin overlying the sensory organ increased firing rate wheras warming led to transient decrease in frequency. The thermal sensitivity or receptors was found to depend on threshold to electric current.