Table 1.

Lack of effect of 50μm streptomycin on shortening, [Ca²⁺]_i and electrical activity of unstretched, single guinea-pig ventricular myocytes

	Control	Streptomycin	Cells
Cell shortening (μm)	2.82 ± 0.34	2.86 ± 0.34	12
[Ca2+]i, transient (340 nm/380 nm ratio units)	0.049 ± 0.005	0.049 ± 0.005	12
Resting membrane potential (mV)	-82 ± 2	-81 ± 2	6
Action potential duration at 90% repolarisation (ms)	337 ± 36	324 ± 48	6
Membrane current amplitude (nA)
Ica,L	0.64 ± 0.06	0.63 ± 0.05	11
IKr	0.08 ± 0.01	0.09 ± 0.01	6
IKs	0.04 ± 0.01	0.04 ± 0.01	9

Mean data for the amplitude of cell shortening and [Ca²⁺]_i, transient, measured simultaneously in fura-2-loaded cells, resting membrane potential and action potential duration at 90% repolarisation, amplitude of L-type Ca²⁺ current (I_Ca,L), and the rapid (I_Kr) and slow (I_Ks) components of the delayed rectifier K⁺ current. Exposure to 50 μm streptomycin had no significant effect on any of these parameters (P > 0.05, paired t test).