Table 1.

Analysis of amperometric spikes from infected chromaffin cells

	pSFV1EGFP-A×2S	pSFV1EGFP-A×2AS	pSFV1EGFP-SubX	pSFV1EGFP-XM
Total cell recorded	36	32	37	30
Total number of spike	1382	224	1299	182
No. of spike/cell	38±3	7±1	35±3	6±2
Rise-time (ms)	7.4±0.5	7.2±0.6	6.9±0.4	7.1±0.4
Fall-time (ms)	17±1.1	15.3±1.5	16.2±1.2	14.9±1.6
Half width (ms)	8.9±0.6	9.1±0.3	9.2±0.5	8.7±0.3
Ave. height (pA)	148±16	138±21	156±19	143±14
Total charge/spike (pC)	1.56±0.16	1.48±0.20	1.68±0.13	1.60±0.18

Amperometric responses were recorded on an expanded time base to avoid overlapping of the spikes. Spikes were only analyzed if they had a base width >10 ms and an amplitude >40 pA. In this way, analyzes were confined to spikes arising immediately beneath the carbon fiber to limit effects on the data of catecholamine diffusion from distant release sites. Spike characteristics were obtained through analysis of amperometric recordings by using Scope version 3.3 software.