TABLE IV.

Effects of [Mg²⁺] on Event Frequency in the Rat

	[Mg2+], mM
	40.0	10.0	4.0	2.0	1.0	0.5	0.2
073001a				0.83
073101a					2.28	4.92
073101c						3.43	5.25
091101a		0.40	1.33	5.65
091301b		0.30	2.67	2.81
091301c		0.25	0.75	4.71
091301d			0.73	5.11
091701a				3.52	2.90	1.83
091701b			0.45	2.85	1.48	2.65
092001a	0.10	0.32
093003a				5.02	6.18
093003b				3.83	4.94
100903a				4.06			3.36
Averages	0.10	0.32	1.19	3.84	2.22	3.99	4.3
SEM		0.04	0.40	0.45	0.41	0.67	0.95

Scans were parallel to the fiber axis. Frequencies are events per second per 100 μm of fiber. In all fibers, at least one of the concentrations was applied twice. In most cases, several passes were made through two or more concentrations and all images at the same concentration were pooled. Averages are of equally weighted frequencies for individual experiments. Nominal [Ca²⁺]_cyto was in all cases 100 nM.