Endogenous opiate peptides in the spinal cord are involved in the analgesia of hypothalamic paraventricular nucleus in the rat.
Many studies have shown that hypothalamic paraventricular nucleus (PVN) plays a role in pain process, and endogenous opiate peptide system in the spinal cord is involved in nociception. This communication was designed to study the relationship between PVN and endogenous opiate system in the spinal cord in the rat. The results showed that in both the thoracic and the lumber spinal cord, microinjection of 100 ng L-glutamate sodium into PVN could increase leucine-enkephalin (L-Ek), beta-endorphin (beta-Ep), dynorphinA(1-13) (DynA(1-13)) concentrations and PVN cauterization decreased L-Ek and beta-Ep concentrations. Pretreatment of the spinal cord with 5 microg naloxone, an opiate receptor antagonist could partly reverse the analgesia induced by microinjection of 100 ng L-glutamate sodium into PVN. The data suggested that PVN analgesia might be involved in the endogenous opiate peptide system in the spinal cord independently.
Yang
Jun
J
Jiangsu Research Institute for Novel Pharmaceuticals, Yangtze River Pharmaceutical Group, Taizhou, China. yj6676@yahoo.com
Yang
Yu
Y
Chu
Jiegen
J
Wang
Gen
G
Xu
Hongtao
H
Liu
Wen-Yan
WY
Wang
Cheng-Hai
CH
Lin
Bao-Cheng
BC
D000698:Analgesia; D000818:Animals; D018698:Glutamic Acid / Q000008:administration & dosage; D008297:Male; D008845:Microinjections; D009270:Naloxone / Q000008:administration & dosage; D009292:Narcotic Antagonists / Q000008:administration & dosage; D018847:Opioid Peptides / Q000008:administration & dosage / Q000378:metabolism / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism*
D009292:Narcotic Antagonists; D018847:Opioid Peptides; D009270:Naloxone; D018698:Glutamic Acid