TABLE 1.

Decay and propagation properties of Ca²⁺ transients in neurons in intact ganglia and in culture

	Intact	Cultured nonuniform	Cultured uniform
Number of cells	7	23	7
Decay half-time at periphery
Nonnuclear (ms)	240 ± 26	195 ± 15	113 ± 26
Nuclear	281 ± 42	330 ± 60	350 ± 110
Radial propagation from periphery
Linear velocity into cytoplasm (μm ms−1/2)	0.09 ± 0.02	0.12 ± 0.02	0.13 ± 0.01
Square-root velocity into nucleus (μm ms−1)	0.9 ± 0.3	0.86 ± 0.03	0.76 ± 0.19

Decay times from peak to half-maximum at peripheral hot spots were calculated in seven cells from intact ganglia, as well as in 23 cultured neurons exhibiting nonuniform peripheral Ca²⁺ responses. Decay times at the periphery of cultured cells with uniform peripheral responses were collected from seven cells in the unbiased sample. In the cultured uniform cells, the decay half-times were calculated at one AOI in the peripheral perinuclear zone and in another peripheral AOI of similar size and shape approximately across the cell from the nucleus. These two AOIs corresponded to the perinuclear and nonnuclear hot spots in neurons of intact ganglia and in cultured neurons exhibiting nonuniform Ca²⁺ responses. The eighth uniformly responding cell of the unbiased sample (not included in the table) had a half-time decay >1 s in both the nuclear and nonnuclear periphery, which thus could not be estimated using our l-s sampling interval. Propagation from the nuclear AOI through the nucleoplasm was characterized by the square-root velocity, whereas the linear velocities were used to determine the rate of propagation through the nonnuclear ER-rich zone (see Figs. 2, 3, and 7).