Effect of somatostatin and its antagonist on morphine analgesia in mice.
Abstract
AIM:
To study the effects of somatostatin (SST) and its antagonist cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr [Bzl]) (SSA) on morphine-induced analgesia.
METHODS:
The pain assays were the hot plate and the tail flick test.
RESULTS:
SST or SSA per se administered intracerebrally at the doses of 0.1 and 1 mg/mouse did not change the pain threshold of mice both in the hot plate and in the tail flick test. However, at the higher dose (10 mg/mouse), SST and SSA decreased the pain threshold in the tail flick test only. SST and SSA administered at the dose of 0.1 mg/mouse did not change morphine-induced analgesia. By contrast, SST and SSA at the doses of 1 and 10 mg/mouse reduced morphine analgesia effects both in the hot plate as well as in the tail flick test.
CONCLUSION:
Our results indicate that SSA as well as SST may be useful in studying pain mechanisms.
Keywords:
To study the effects of somatostatin (SST) and its antagonist cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr [Bzl]) (SSA) on morphine-induced analgesia.
METHODS:
The pain assays were the hot plate and the tail flick test.
RESULTS:
SST or SSA per se administered intracerebrally at the doses of 0.1 and 1 mg/mouse did not change the pain threshold of mice both in the hot plate and in the tail flick test. However, at the higher dose (10 mg/mouse), SST and SSA decreased the pain threshold in the tail flick test only. SST and SSA administered at the dose of 0.1 mg/mouse did not change morphine-induced analgesia. By contrast, SST and SSA at the doses of 1 and 10 mg/mouse reduced morphine analgesia effects both in the hot plate as well as in the tail flick test.
CONCLUSION:
Our results indicate that SSA as well as SST may be useful in studying pain mechanisms.