Research ReportPotassium-selective microelectrode revealed difference in threshold potassium concentration for cortical spreading depression in female and male rat brain

It has been found with potassium-selective microelectrodes that the threshold extracellular concentration of potassium [K+]e for eliciting fast spreading depression from the site of administration 1.5 mm away is 80% lower in the rat female cortex (8.0 ± 0.6 mM) than in the male cortex (14.4 ± 0.4 mM). The rate of the first slow phase of [K+]e rise before reaching the threshold and speed of SD propagation were similar for both sexes as well as the rise of the second active fast phase of the [K+]e increase. Lower [K+]e threshold in females can facilitate the rapid K+ release from the nerve tissue cells that may cause a cerebrovascular vasodilatation and the attack of migraine pain.

Graphical Abstract194Research Highlights► Potassium-selective microelectrodes (ISE) were inserted into rat cortex. ► Spreading depression (SD) was started by application of 1 M KCl. ► Threshold for SD was 14 mM K+ in males, but only 8 mM for females. ► Lower K+ threshold can explain the predisposition of women to migraine.