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Table 1 Intrinsic electrogenic properties of small-sized DRG neurons in naïve, PBS-, HK-, and MRMT-1-rats

From: Enhanced excitability of small dorsal root ganglion neurons in rats with bone cancer pain

   RMP Rin CT TP TP rise rate AP amplitude AP overshot AP duration AHP amplitude AHP80% duration AP frequency
   mV pA mV v/s mV mV ms mV ms Spikes/s
CT < 50 pA Naïve -50.6 ± 0.5 (29) 654.0 ± 20.1 (33) 29.8 ± 2.0 (29) -27.6 ± 0.8 (38) 0.8 ± 0.1 (30) 101.8 ± 1.9 (34) 55.9 ± 1.4 (34) 44.6 ± 2.9 (30) 19.2 ± 0.8 (40) 17.6 ± 1.1 (35) 20.5 ± 1.8 (30)
  PBS -50.3 ± 0.7 (18) 634.5 ± 28.5 (13) 28.9 ± 2.2 (18) -27.8 ± 0.8 (29) 0.7 ± 0.1 (24) 103.4 ± 1.8 (24) 55.5 ± 1.6 (24) 43.2 ± 2.6 (23) 18.9 ± 1.3 (25) 17.7 ± 1.4 (21) 20.6 ± 2.3 (14)
  MRMT-1 -45.6 ± 0.5 (52) *** 546.3 ± 15.3 (60) *** 20.9 ± 1.5 (44) *** -30.7 ± 0.6 (55) ** 0.9 ± 0.1 (45) * 94.2 ± 1.9 (55) ** 45.7 ± 1.9 (47) *** 34.3 ± 1.4 (54) *** 14.7 ± 0.7 (51) *** 14.6 ± 0.6 (49) * 31.4 ± 1.9 (32) ***
  HK -50.5 ± 0.6 (13) 638.1 ± 24.9 (19) 28.9 ± 2.4 (13) -26.6 ± 1.0 (23) 0.7 ± 0.1 (13) 102.6 ± 2.6 (16) 54.7 ± 1.7 (16) 44.7 ± 3.1 (16) 19.7 ± 1.3 (11) 18.2 ± 1.7 (13) 20.3 ± 2.6 (12)
  Naïve -51.7 ± 1.1 (12) 593.0 ± 22.3 (14) 85.0 ± 3.3 (13) -20.1 ± 0.7 (19) 1.9 ± 0.2 (11) 104.7 ± 3.4 (17) 55.1 ± 1.9 (17) 24.5 ± 2.1 (15) 19.7 ± 1.5 (16) 10.6 ± 1.4 (16) 10.5 ± 1.7 (15)
CT50 ~100 pA PBS -51.1 ± 0.6 (7) 594.6 ± 25.4 (6) 86.4 ± 4.0 (7) -19.9 ± 1.5 (6) 2.0 ± 0.3 (5) 105.1 ± 4.3 (6) 56.5 ± 3.1 (6) 24.0 ± 1.9 (6) 20.2 ± 2.6 (7) 11.2 ± 1.7 (7) 13.8 ± 2.2 (6)
  HK -52.6 ± 1.5 (11) 596.9 ± 26.4 (7) 85.5 ± 2.7 (11) -20.0 ± 1.1 (10) 2.0 ± 0.2 (10) 104.0 ± 2.4 (10) 56.0 ± 2.6 (9) 24.0 ± 1.7 (8) 19.7 ± 2.1 (8) 10.7 ± 1.5 (9) 12.2 ± 3.4 (9)
  MRMT-1 -48.6 ± 0.5 (16) ** 486.5 ± 25.8 (17) ** 72.2 ± 4.0 (16) * -23.4 ± 1.0 (17) ** 2.3 ± 0.2 (14) 98.7 ± 2.6 (17) 46.1 ± 2.9 (15) * 22.1 ± 1.2 (17) 14.4 ± 1.3 (17) * 11.4 ± 1.0 (17) 19.3 ± 3.2 (12) *
CT > 100 pA Naïve -54.6 ± 2.1 (7) 550.5 ± 40.8 (9) 157.9 ± 12.6 (7) -16.6 ± 1.0 (8) 5.4 ± 1.1 (5) 103.7 ± 3.6 (7) 54.1 ± 3.3 (5) 17.5 ± 3.2 (6) 10.8 ± 1.3 (8) 6.3 ± 0.6 (6) 7.1 ± 3.4 (8)
  PBS -54.1 ± 1.9 (7) 556.6 ± 35.3 (7) 158.6 ± 14.6 (7) -18.8 ± 0.8 (9) 5.1 ± 0.7 (5) 107.9 ± 4.8 (7) 56.7 ± 3.7 (6) 15.1 ± 1.1 (6) 10.9 ± 1.8 (6) 6.1 ± 0.5 (5) 6.8 ± 2.9 (8)
  HK -54.2 ± 1.6 (6) 552.0 ± 28.5 (6) 163.3 ± 13.2 (6) -17.0 ± 1.2 (7) 5.1 ± 1.2 (5) 106.9 ± 6.3 (7) 56.2 ± 2.4 (6) 17.0 ± 4.6 (6) 10.6 ± 1.8 (6) 6.3 ± 0.6 (6) 7.3 ± 2.6 (6)
  MRMT-1 -51.2 ± 0.9 (13) 508.1 ± 24.9 (12) 161.7 ± 16.6 (9) -20.2 ± 1.4 (9) 5.0 ± 0.9 (7) 103.3 ± 4.9 (10) 54.9 ± 2.6 (8) 13.9 ± 1.4 (9) 9.0 ± 1.39 (10) 6.3 ± 0.9 (7) 10.0 ± 4.3 (8)
  1. Values are presented as mean ± S.E.M with the number given in parentheses. *p < 0.05, **p < 0.01,***p < 0.001, as compared with HK groups, two-tailed Student's t-test. RMP: resting membrane potential; Rin: membrane input resistance; CT: the depolarized current threshold for evoking the 1st action potential; TP: threshold potential; AHP: afterhyperpolarization; AHP80% duration: AHP duration at 80% repolarization (AHP80%);
  2. AP: action potential. Note that implantation of MRMT-1 tumor cells into the tibial canal in rats increased the cells excitability in low (CT < 50 pA)-, medium (CT: 50 - 100 pA)-, but not high (CT > 100 pA)-firing threshold DRG neurons as assessed by the intrinsic electrogenic parameters.