Table 1.
Influence of sodium substitutes on 5-HT-induced [14C]guanidinium influx in N1E-115 cells
| Response to 5-HT | |||
|---|---|---|---|
| n | pEC50±s.e.m. | Emax±s.e.m. | |
| (mean EC50; μM) | (% of reference) | ||
| Sodium (135 mM) | 12 | 5.89±0.09 (1.3) | 58.3±6.2 |
| Sodium : choline | 5 | 5.22±0.02* (6.0) | 60.4±1.4 |
| (118.3 : 16.9 mM) | |||
| Sodium:choline | 5 | 4.89±0.07* (12.3) | 66.5±2.0 |
| (101.3 : 33.8 mM) | |||
| Sodium : choline | 5 | 4.62±0.07* (24.5) | 79.9±4.5* |
| (67.5 : 67.5 mM) | |||
| Choline (135 mM) | 9 | 4.33±0.01* (44.7) | 110.2±3.1* |
| Lithium (135 mM) | 4 | 5.69±0.09 (2.3) | 40.6±1.9* |
| TMA (135 mM) | 7 | 4.73±0.01* (19.1) | 108.8±5.4* |
| Tris (135 mM) | 7 | 5.58±0.02* (3.6) | 97.7±6.2* |
| NMDG (135 mM) | 8 | 5.95±0.01 (1.3) | 93.4±7.8* |
The pEC50 and Emax values of 5-HT (2 min exposure to each concentration) under the cation conditions indicated were calculated from the concentration–response curves shown in Figures 2 and 3. The respective maximal responses (Emax) are expressed as percentages of the effect elicited by 100 μM 5-HT using choline (135 mM) buffer (=reference effect). Shown are means±s.e.m.
*
Significantly different from pEC50 and Emax at 135 mM sodium.