Carrageenan-Induced Hyperalgesia Is Partially Alleviated by Endomorphin-1 Locally Delivered into Inflamed Paws In Rat
The Korean Journal of Physiology and Pharmacology
;
: 369-373, 2003.
Article
in English
| WPRIM
| ID: wpr-727391
ABSTRACT
This study was performed to test whether endomorphin-1 has analgesic effect, when locally administrated into inflamed peripheral tissue. Carrageenan suspension (0.5%) was injected intraplantarly into the right paw of Sprague-Dawley male rats, and the rats were subjected to a series of mechanical stimuli with von Frei filaments before and after the injection. Carrageenan-injected rats showed typical inflammatory hyperalgesic signs and decrease of withdrawal threshold, peaked at 3 to 6 hours after the injection and lasted more than 3 days. Endomorphin-1 was intraplantarly injected with carrageenan, simultaneously or 3~4 hours after carrageenan. Simultaneous injection of endomorphin-1 with carrageenan significantly reduced hyperalgesia and thd analgesic effect was prolonged up to 8 hours. The delivery of endomorphin-1 (50 microgram) into the inflamed area after 3 to 4 hours of carrageenan injection significantly increased the threshold of hyperalgesic mechanical withdrawal response, but only partially. Intrathecal treatment of endomorphin-1 completely reversed carrageenan-induced hyperalgesia. This report is the first to show that peripherally delivered endomorphin-1 relieved inflammatory hyperalgesia. But a control through peripheral mu-opioid receptors appears to be not sufficient for complete pain treatment.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Carrageenan
/
Rats, Sprague-Dawley
/
Hyperalgesia
/
Inflammation
Limits:
Animals
/
Humans
/
Male
Language:
English
Journal:
The Korean Journal of Physiology and Pharmacology
Year:
2003
Type:
Article
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