Intrathecal pramipexole and selegiline for sensory and motor block in rats

Background The purpose of the study was to investigate spinal sensory and motor block by antiparkinsonian drugs (pramipexole and selegiline), and the combination of pramipexole and the local anesthetic lidocaine. Methods Using a technique of spinal blockade in rats, the effects of pramipexole, selegiline, and coadministration of pramipexole and lidocaine on spinal blockades of motor and sensory function were investigated. Results Under a concentration of 100 mM, pramipexole displayed more potent and had a longer duration of nociceptive, proprioceptive, and motor block than selegiline, whereas pramipexole and selegiline were less potent in comparison to lidocaine. Pramipexole produced spinal nociceptive, proprioceptive, and motor blocks in a dose-related manner. On the ED50 (50% effective dose) basis, the rank-order potency on nociceptive, proprioceptive, and motor block was pramipexole < lidocaine. The spinal block duration of pramipexole was greater than lidocaine at every equipotent dose tested (ED25, ED50, and ED75). Coadministration of lidocaine (ED50 or ED95) with pramipexole (4.5 mu mol/kg) improved the effect (efficacy) and duration of the spinal block. Conclusions Pramipexole and selegiline were less potent than lidocaine to block sensory and motor responses. The duration of the spinal anesthetic effect of pramipexole was longer than lidocaine. At a non-effective dose, pramipexole increased the duration of efficacy of lidocaine.

Automated summary

This study investigated the sensory and motor block effects of antiparkinsonian drugs (pramipexole and selegiline) and the combination of pramipexole and lidocaine on spinal blockade. Pramipexole displayed more potent and longer-lasting block effects compared to selegiline, but both were less potent than lidocaine. When coadministered with lidocaine, pramipexole improved the efficacy and duration of the spinal block. Overall, pramipexole showed promise in enhancing the effectiveness of lidocaine as a spinal anesthetic.