Effects of i.t. pretreatment with antiserum against dynorphin A(1-17), [Leu]-enkephalin, [Met]-enkephain β-endorphin, cholecystokinin, and substance P on i.t. morphine-produced antianalgesia against i.t. morphine-induced TF inhibition Groups of mice were pretreated i.t. with antiserum against dynorphin A(1-17), [Leu]-enkephalin, [Met]-enkephain, β-endorphin, cholecystokinin (200 μg), or substance P (10 μg) 1 h before i.t. morphine (0.3 nmol) injection and were then injected i.t. with morphine (3 nmol) 45 min after morphine injection. The TF response was measured 15 min thereafter. Data are expressed as mean ± S.E.M. One-way ANOVA was used to test the difference between groups. (n) represents the number of mice studied in each group.
Antiserum (n) | Morphine (0.3 nmol) i.t. Pretreatment | TF Inhibition (%MPE) by i.t. Morphine (3 nmol) |
|---|---|---|
| Normal rabbit serum (9) | No | 77.79 ± 8.09 |
| Normal rabbit serum (8) | Yes | 27.78 ± 3.56 |
| A/S against dynorphin A (1-17) (8) | Yes | 26.55 ± 4.97 |
| A/S against [Leu]-enkephalin (8) | Yes | 40.73 ± 6.01 |
| A/S against [Met]-enkephalin (9) | Yes | 27.46 ± 4.04 |
| A/S against β-endorphin (7) | Yes | 22.65 ± 5.37 |
| A/S against cholecystokinin (8) | Yes | 29.44 ± 3.64 |
| A/S against substance P (8) | Yes | 33.80 ± 6.11 |
A/S, antiserum.