Table 1.
Effects of prucalopride and inhibitors of 5-HT4 receptor, PKA, CREB, gene transcription, and protein synthesis on electrophysiological measures of excitability in NA neurons isolated from naïve rats. Each inhibitor listed represents a separate study.
| Inhibitor study (target) | Testing condition | RMP (mV) a | AP volt. thresh. (mV) a | Rheobase (pA) a | Cm (pF) a | SA incidence (%) b |
|---|---|---|---|---|---|---|
|
GR113808 (5-HT4R) Delayed c |
Vehicle | −66.8 (−80.3, −59) (20) |
−35 (−46.7, −24.9) (20) |
120 (60, 240) (20) |
30.5 (18, 43) (20) |
0 (0/20) |
| Ppr | −66.4 (−76.2, −48.7) (19) |
−39.2 (−50, –23.8) (17) * |
100 (60, 220) (17) |
33 (21, 40) (18) |
5.3 (1/19) |
|
| Ppr, GR | −63.9 (−76.7, −52.1) (16) |
−36.7 (−48.4, −27.8) (16) |
100 (40, 220) (16) |
33.5 (23, 55) (16) |
0 (0/16) |
|
| GR | −61.3 (−80.1, −56.2) (12) |
−37.3 (−47, −30.1) (12) |
80 (20, 200) (11) |
27 (14, 39) (12) |
8.3 (1/12) |
|
| H-89 (PKA) |
Vehicle | −68.5 (−72.9, −58.3) (15) |
−37.6 (−47.8, −24.9) (15) |
100 (60, 240) (15) |
30 (18, 46) (15) |
0 (0/15) |
| Ppr | −67.2 (−88.7, −51.7) (15) |
−39.2 (−51.3, –23.8) (15) |
80 (0, 220) (15) |
33 (20, 40) (15) |
0 (0/15) |
|
| Ppr + H-89 | −63.7 (−73.6, −50) (16) |
−37.9 (−46.3, −29.1) (16) |
100 (40, 180) (16) |
27.5 (19, 45) (16) |
0 (0/16) |
|
| H-89 | −63.2 (−73, −48.1) (14) |
−34.7 (−47.8, −27.6) (14) |
90 (20, 240) (14) |
27 (15, 33) (14) |
7.1 (1/14) |
|
| 666–15 (CREB) |
Vehicle | −71.5 (−80.6, −60.3) (27) |
−38.9 (−54.4, −29) (27) |
120 (20, 600) (27) |
31 (20, 42) (27) |
7.4 (2/27) |
| Ppr | −69.5 (−81.1, −45) (26) |
−40.6 (−47.8, –32.2) (26) |
90 (20, 280) (26) |
32.5 (18, 41) (26) |
11.5 (3/26) |
|
| Ppr + 666–15 | −67.2 (−75.7, −50.6) (33) ** |
−38 (−47.3, −31.7) (31) |
90 (20, 340) (32) |
31 (15, 44) (33) |
0 (0/33) |
|
| 666–15 | −70.7 (−81.8, −53.1) (16) |
−40.9 (−47.9, −29) (15) |
100 (20, 220) (16) |
36 (26, 43) (16) |
0 (0/16) |
|
| ActD (mRNA synthesis) |
Vehicle | −71.2 (−79.3, −53.6) (20) |
−40.3 (−44.5, −29.4) (20) |
90 (20, 220) (20) |
31.5 (15, 41) (20) |
0 (0/20) |
| Ppr | −71.3 (−77.9, −53.7) (22) |
−41.1 (−47.6, −34.3) (22) |
80 (20, 140) (22) |
29 (17, 39) (21) |
4.5 (1/22) |
|
| Ppr + ActD | −75.3 (−83.9, −68.8) (13) * |
–33 (−41.3, −28.1) (13) $ |
180 (20, 340) (13) # |
29 (16, 39) (13) |
0 (0/13) |
|
| ActD | −75.2 (−79.3, −58.2) (12) |
−29.4 (−35.5, –22.9) (12) $ |
240 (20, 360) (12) ### |
29.5 (18, 38) (12) |
8.3 (1/12) |
|
| Chx (protein synthesis) |
Vehicle | −71.9 (−77.7, −61.1) (15) |
−38.4 (−43.8, −29.4) (15) |
100 (20, 240) (15) |
31 (21, 40) (15) |
0 (0/15) |
| Ppr | −71.4 (−81, −54.3) (17) |
−41 (−48.8, −36.4) (17) |
60 (20, 180) (17) |
29 (14, 45) (17) |
11.8 (2/17) |
|
| Ppr + Chx | −71.1 (−79.6, −63.7) (21) |
−38 (−49.7, −29.8) (20) |
140 (40, 240) (20) |
25.5 (17, 37) (20) $ |
0 (0/21) |
|
| Chx | −72.2 (−83.6, −59.9) (9) |
−39.5 (−44.1, −30.9) (9) |
120 (40, 180) (9) |
32 (21, 34) (9) |
0 (0/9) |
Values are reported as medians (minimum, maximum) (number of cells sampled). b Values are reported as incidences in percentages (number of cells showing spontaneous firing / number of cells sampled). c GR113808 application was delayed until after the washout of Ppr, and it remained overnight. All other inhibitors were applied concurrently with Ppr. Each experimental group was tested against vehicle. Statistical tests: Kruskal-Wallis followed by Dunn’s multiple comparisons tests (* p < 0.05, ** p < 0.01, *** p < 0.0001); Brown-Forsythe and Welch ANOVA followed by Dunnett’s T3 multiple comparisons tests (# p < 0.05, ## p < 0.01, ### p < 0.001); ordinary one-way ANOVA followed by Dunnett’s multiple comparisons tests ($ p < 0.05, $$ p < 0.01, $$$ p < 0.001). ActD, actinomycin D; AP volt. thresh., action potential voltage threshold; Chx, cycloheximide; Cm, membrane capacitance; Ppr, prucalopride; RMP, resting membrane potential; SA, spontaneous activity.