. 2003 Jan 3;547(Pt 1):255–269. doi: 10.1113/jphysiol.2002.035857

Table 3.

Comparison of the electrophysiological properties of native bovine and sheep parotid Kir currents and bKir2.1 expressed in HEK293 cells

	bKir2.1 current	Native Kir current of bovine parotid acinar cells	Native Kir current of sheep parotid acinar cells
Whole-cell current
Type of rectification	Strong	Strong	Strong
Inward conductance (G) ([K⁺]_o= 5 mM)	11 nS	28 nS	24 nS
[K⁺]_o dependency of G	[K⁺]_o^0.52	[K⁺]_o^0.57	[K⁺]_o^0.51
Conductance sequence	K⁺≫ Rb⁺= Na⁺	K⁺≫ Rb⁺= Li⁺= Na⁺	K⁺≫ Na⁺
Permeability sequence	^*	K⁺ > Rb⁺≫ Li⁺= Na⁺	K⁺≫ Na⁺
Ba²⁺block	K_d(0) = 8 μM, δ= 0.36	K_d(0) = 12 μM, δ= 0.36	K_1/2= 1 μM (at −140 mV)
Cs⁺block	K_d(0) = 116 mM, δ= 1.40	K_d(0) = 121 mM, δ= 1.15	K_1/2= 100 μM (at −140 mV)
Single channel current
Inward conductance (γ)	27 and 16 pS	27 pS(γ_max= 29.6 pS, K_m= 23.8 mM)	29 pS (γ_max= 33.4 pS, K_m= 36.8 mM)
[K⁺]_o dependency of γ	—	[K⁺]_o^0.42	[K⁺]_o^0.55

The selectivity sequence based on permeability (P_X/P_K) ratio could not be estimated properly because Ba²⁺-sensitive inward and outward currents were very small when Rb⁺ or Na⁺ was in the bath and such a small Ba²⁺-sensitive current was also observed in mock-transfected cells under the same experimental conditions (data not shown).

Data for bKir2.1 currents were obtained from 5–28 experiments. Values are means.