Mechanically induced electrical and intracellular calcium responses in normal and cancerous mammary cells.
Mechanically induced channel activities and increase of intracellular calcium ([Ca2+]i) in normal and cancerous murine mammary cells (MMT 060562) were investigated using the patch clamp technique and Fura-2 fluorescence. Both cell types showed similar properties. Upon mechanical stimulation, activation of the Ca(2+)-dependent K+ channel or outward membrane current was recorded in cells which were several cells distant from the stimulated cell. Mechanical stimulation also induced an increase of [Ca2+]i in the touched cell, and this increase of [Ca2+]i spread to the surrounding cells. The [Ca2+]i signal travelled a distance of 100-200 microns within 20-40 s and then diminished. The presence of cell-to-cell communication between adjacent mammary cells through gap junction was indicated by injection of lucifer yellow and measurements of electrical coupling (coupling constant = 0.2-0.3). The mechanically induced increase of the [Ca2+]i signal spread to adjacent cells even when the stimulated cell had no physical contact with them. In the absence of fluid movement, the pattern of the spread of the [Ca2+]i signal was a concentric circle. However, in the presence of fluid movement, the pattern changed to elongate to the direction of the flow. These findings suggested that a certain factor was released from the mechanically stimulated cell to the extracellular space, and this factor induces the increase of [Ca2+]i in surrounding cells.
Enomoto
K
K
Department of Physiology, Shimane Medical University, Japan.
Furuya
K
K
Yamagishi
S
S
Maeno
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002450:Cell Communication / Q000502:physiology*; D002478:Cells, Cultured; D004553:Electric Conductivity; D004558:Electric Stimulation; D005260:Female; D007365:Intercellular Junctions / Q000502:physiology; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism*; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D008839:Microelectrodes; D010812:Physical Stimulation; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D014741:Video Recording
D015221:Potassium Channels; D002118:Calcium