Table 7 Skin temperature, thermal threshold (TT) and thermal excursion (%TE) and ambient temperature following a single oral administration of saline, 0.3, 0.6 and 1.2 mg/kg codeine and intravenous 0.2 mg/kg morphine to 7 horses. Values are expressed as mean ± SD
Dose Group | Time (h) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
0 | 0.25 | 0.5 | 0.75 | 1 | 1.5 | 2 | 3 | 4 | 6 | |
Skin Temp (°C) | ||||||||||
 Saline | 27.4 ± 2.2 | 27.8 ± 2.2 | 27.4 ± 2.4 | 27.8 ± 2.6 | 28.3 ± 2.4 | 28.8 ± 1.7 | 29.5 ± 1.7* | 30.9 ± 0.5* | 31.0 ± 0.6* | 31.3 ± 1.1* |
 0.3 mg/kg | 27.6 ± 3.5 | 27.1 ± 3.1 | 27.7 ± 3.3 | 28.3 ± 3.9 | 28.8 ± 3.9 | 29.3 ± 3.0* | 29.1 ± 3.3 | 30.7 ± 1.8* | 31.6 ± 0.7* | 31.9 ± 1.0* |
 0.6 mg/kg | 28.2 ± 1.5 | 28.7 ± 1.3 | 28.3 ± 2.2 | 28.4 ± 2.8 | 28.4 ± 2.7 | 28.8 ± 2.4 | 28.8 ± 1.9 | 31.3 ± 1.1* | 31.2 ± 0.9* | 31.9 ± 0.6* |
 1.2 mg/kg | 26.8 ± 3.7 | 26.8 ± 3.7 | 27.2 ± 4.1 | 27.9 ± 4.3 | 28.8 ± 3.2* | 28.8 ± 3.1* | 29.9 ± 2.8* | 31.3 ± 1.5* | 31.5 ± 1.2* | 32.1 ± 0.6* |
 Morphine | 26.8 ± 3.6 | 26.0 ± 3.3 | 25.9 ± 2.9 | 27.2 ± 3.0 | 28.0 ± 3.3 | 28.4 ± 3.8 | 28.8 ± 3.8* | 30.4 ± 4.1* | 30.3 ± 3.5* | 31.1 ± 0.8* |
TT (°C) | ||||||||||
 Saline | 48.5 ± 4.4 | 44.7 ± 3.0* | 46.0 ± 3.5 | 45.4 ± 2.8 | 47.6 ± 4.9 | 46.4 ± 3.3 | 47.0 ± 3.7 | 49.3 ± 4.2 | 48.4 ± 4.0 | 50.3 ± 5.1 |
 0.3 mg/kg | 48.8 ± 4.6 | 46.9 ± 6.9 | 50.0 ± 5.5 | 46.7 ± 7.5 | 48.5 ± 9.2 | 47.8 ± 5.1 | 51.9 ± 4.6 | 50.2 ± 6.1 | 49.6 ± 5.2 | 50.6 ± 4.3 |
 0.6 mg/kg | 48.0 ± 4.8 | 46.1 ± 5.3 | 45.9 ± 6.2 | 48.9 ± 4.7 | 47.3 ± 4.4 | 48.9 ± 5.3 | 48.2 ± 4.7 | 50.4 ± 5.1 | 48.5 ± 5.9 | 52.1 ± 3.8* |
 1.2 mg/kg | 48.8 ± 4.3 | 47.5 ± 4.7 | 49.7 ± 4.1 | 48.8 ± 4.5 | 47.5 ± 5.3 | 49.5 ± 3.1 | 50.4 ± 4.1 | 48.5 ± 2.6 | 50.5 ± 4.1 | 49.4 ± 4.5 |
 Morphine | 48.3 ± 4.5 | 49.6 ± 5.4 | 50.8 ± 3.6 | 50.6 ± 3.8 | 49.6 ± 4.2 | 50.0 ± 4.1 | 50.2 ± 4.9 | 50.8 ± 3.0 | 50.6 ± 4.6 | 49.2 ± 2.5 |
% TE | ||||||||||
 Saline | 75.5 ± 17.2 | 60.8 ± 11.2 | 66.4 ± 11.3 | 66.4 ± 10.1 | 70.1 ± 18.5 | 65.3 ± 14.5 | 67.4 ± 13.3 | 74.9 ± 16.7 | 71.1 ± 16.6 | 79.2 ± 17.3 |
 0.3 mg/kg | 77.3 ± 14.4 | 70.5 ± 21.7 | 81.2 ± 16.9 | 68.4 ± 23.8 | 76.4 ± 29.2 | 71.1 ± 19.3 | 87.2 ± 17.1* | 78.7 ± 25.0 | 75.3 ± 21.6 | 79.5 ± 17.3 |
 0.6 mg/kg | 73.0 ± 17.6 | 65.4 ± 19.0 | 65.6 ± 20.1 | 74.8 ± 18.4 | 69.7 ± 17.4 | 75.4 ± 20.8 | 72.8 ± 17.6 | 79.2 ± 21.3 | 71.1 ± 24.7 | 86.3 ± 15.3 |
 1.2 mg/kg | 77.0 ± 15.9 | 73.1 ± 17.9 | 79.5 ± 14.2 | 75.2 ± 16.8 | 69.5 ± 20.6 | 77.3 ± 11.8 | 79.6 ± 17.4 | 70.6 ± 11.3 | 79.7 ± 17.1 | 73.7 ± 19.3 |
 Morphine | 75.2 ± 15.0 | 80.7 ± 19.0 | 84.8 ± 12.3 | 83.4 ± 13.4 | 79.7 ± 14.4 | 80.3 ± 15.7 | 81.7 ± 17.3 | 82.6 ± 13.5 | 81.9 ± 17.0 | 75.9 ± 13.6 |
Ambient Temp (°C) | ||||||||||
 Saline | 20.0 ± 1.2 | 20.1 ± 1.3 | 20.2 ± 1.4 | 20.3 ± 1.4 | 20.3 ± 1.4 | 20.8 ± 1.4* | 21.1 ± 1.4* | 21.9 ± 1.1* | 22.8 ± 0.9* | 24.3 ± 1.3* |
 0.3 mg/kg | 19.1 ± 1.3 | 19.3 ± 1.3 | 19.4 ± 1.4 | 19.5 ± 1.4* | 19.7 ± 1.5* | 20.0 ± 1.7* | 20.1 ± 1.8* | 21.1 ± 2.0* | 22.3 ± 1.8* | 24.6 ± 1.8* |
 0.6 mg/kg | 19.4 ± 1.6 | 19.6 ± 1.7 | 19.8 ± 1.7 | 19.9 ± 1.6 | 20.0 ± 1.6* | 20.4 ± 1.6* | 20.5 ± 1.8* | 21.6 ± 1.5* | 22.6 ± 1.4* | 24.8 ± 1.9* |
 1.2 mg/kg | 19.5 ± 1.9 | 19.7 ± 1.8 | 19.7 ± 1.8 | 19.9 ± 1.8 | 20.1 ± 1.9 | 20.5 ± 1.9* | 20.8 ± 2.1* | 21.7 ± 2.1* | 22.6 ± 1.9* | 24.5 ± 1.8* |
 Morphine | 19.1 ± 1.7 | 19.3 ± 1.5 | 19.4 ± 1.5 | 19.7 ± 1.5 | 19.9 ± 1.6* | 20.4 ± 1.7* | 20.9 ± 1.8* | 21.7 ± 1.8* | 22.6 ± 1.6* | 23.5 ± 1.7* |