The potassium-sensitivity of isolated embryonic heart cells increases with development

Citations of this article
Mendeley users who have this article in their library.
Get full text


Spontaneously beating myocardial cells isolated from the hearts of chick embryos aged 2-18 days were cultured in medium containing 1.3, 4.2, 8.1, or 12 mM K+. At all ages tested, the percentage of beating cells (% BC) was maximal at 1.3 mM K. In cultures from 2-to 4-day hearts, isolated pacemaker cells were relatively insensitive to the level of extracellular K-concentration (K0). In contrast, the activity of most of the cells from 7- to 18-day hearts was suppressed by high Ko. The first week of heart development, therefore, represents a period of transition from a state of K-insensitivity to one of greater sensitivity of cardiac pacemakers to the level of Ko. Differences in the kinetics of pacemaker-inhibition in response to a sudden increment of Ko were used as evidence for three subpopulations of spontaneously active cells: those in which spontaneous activity was immediately and permanently suppressed; those which stopped beating initially but gradually recovered; and those which were unaffected by an increment in Ko. The relative size of each of these subpopulations was found to change in a systematic way with embryonic age. It is suggested that the change from a state of K-resistance to K-sensitivity of the embryonic pacemakers results either from a change in ionic permselectivity of the pacemaker membranes, or from an alteration in the concentration of ions inside and outside the cells during early development. © 1970.




DeHaan, R. L. (1970). The potassium-sensitivity of isolated embryonic heart cells increases with development. Developmental Biology, 23(2), 226–240.

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free