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. Author manuscript; available in PMC: 2022 Feb 9.
Published in final edited form as: Pharmacol Ther. 2021 Jul 10;230:107961. doi: 10.1016/j.pharmthera.2021.107961

Table 2. Strain differences in opioid-induced behaviours.

Drug Assay Strains Observations References
Morphine Hot water tail flick – 49 °C and 15 s cutoff Four day escalating dose ofmorphine (10-40 mg/kg) used to induce tolerance. Strain – baseline (s)
129P3-2.4 ± 0.1
A – 2.4 ± 0.1
AKR – 2.9 ± 0.2
ABLB/c – 3.1 ± 0.2
C3H/He – 1.8 ± 0.1
C57BL/6-2.2 ± 0.1
CBA – 1.9 ±0.1
DBA/2-2.5 ± 0.1
LP – 2.8 ± 0.1
SJL – 2.2 ± 0.1
SWR – 1.8 ± 0.1

  • Significant differences in baseline latencies.

  • Significant differences in the relative degree of tolerance (from 0.8 to 10.8 fold change in morphine ED50 values (day 1 vs day 4).

 (Kestet al., 2002)
Morphine Hot water tail flick – 55 °C and 10 s cutoff Strain – baseline (s)
SW – 2.7 ± 0.6
129/SvEv – 3.5 ± 0.6

  • Significant differences in baseline latencies.

  • Differences in duration of antinociception (>6 h in 129/SvEv vs 2 h in SW).

  • 129/SvEv mice were approx. 10-fold more sensitive to morphine

 (Crain and Shen, 2000)
Morphine Hot water tail flick – 49 °C and 15 s cutoff Strain – baseline (s)
129/J – 4.7 ± 0.2
129/SvJ – 4.5 ± 0.1
B6-2.6 ± 0.1

  • Significant differences in baseline latencies.

  • Right shifted dose-response curve to cumulative morphine in B6 mice.

 (Mogil & Wilson, 1997)
Morphine LD50 determination by percent survival – measured by return to regular breathing Strain and sex – LD50 (mg/kg)
129S1/SvlmJ F – 631.3
129S1/SvlmJ M -664.2
A/J F – 212.2
A/J M – 225.2
C57BL/6 J F – 311.6
C57BL/6 J M – 254.3
CAST/EiJ F – 882.2
CAST/EiJ M – 429.9
NOD/ShiLtJ F – 811.0
NOD/ShiLtJ M – 588.8
NZO/HILtJ F – 333.9
NZO/HILtJ M – 324.4
PWK/PhJ F – 261.0
PWK/PhJ M – 359.1
WSB/EiJ F – 526.4
WSB/EiJ M – 695.6

  • Baseline respiration data not reported.

  • Significant differences in LD50 values between strains and sex.

 (Bubier et al., 2020)
Morphine Measurement of respiration (whole body plethysmography) and constipation (Charcoal transit) C57BL/6 J
A/J

  • Baseline values not compared between strains.

  • Enhanced sensitivity to morphine respiratory depression and significantly greater constipation in C57BL/6 J mice vs A/J mice

 (Young et al., 2018)

Summary of the assays, strains and results reported in the studies addressing strain differences to opioid sensitivity.