TABLE 1.

Comparison of α-cell calcium oscillation characteristics in response to glucose and inhibitors of glucagon secretion, as measured by Fluo4 imaging

Each α-cell was monitored during 5 min for each condition.

	No. of cells analyzed	% of oscillating cells	Frequency (oscillations/min)	Amplitude of oscillations
				+15–30% increase	+30–60%	>60%
				%	%	%
Islets at 1 mm glucose	168	46	0.89 ± 0.07	56.1 ± 5.6	28.8 ± 3.7	15.1 ± 3.5
Islets at 12 mm glucose	91	49	1.44 ± 0.18a	52.4 ± 7.1	30.8 ± 5.3	16.8 ± 5.2
Islets at 1 mm glucose + 100 nm insulin	60	45	0.71 ± 0.09	63.0 ± 11.8	21.7 ± 6.9	15.2 ± 7.2
Islets at 1 mm glucose + 30 μm zinc	62	40	0.84 ± 0.17	56.4 ± 12.8	30.8 ± 9.7	12.8 ± 5.7
Islets at 1 mm glucose + 1 mm GABA	57	39	0.84 ± 0.14	55.7 ± 13.4	27.3 ± 6.4	17.0 ± 7.7
Islets at 1 mm glucose + 100 nm somatostatin	46	50	0.78 ± 0.09	60.9 ± 8.1	30.5 ± 8.4	8.6 ± 2.9
Isolated cells at 1 mm	45	53	0.89 ± 0.10	55.5 ± 6.6	25.6 ± 6.3	18.9 ± 5.6
Isolated cells at 12 mm	52	52	0.97 ± 0.15	64.5 ± 8.9	20.7 ± 5.3	14.9 ± 6.9
Isolated cells at 1 mm + 30 μm zinc	30	57	0.67 ± 0.10	75.0 ± 13.1	20.3 ± 7.2	4.7 ± 2.6

^a p < 0.01, unpaired Student's t test, as compared with 1 mm glucose.