PMID- 7749752
OWN - NLM
STAT- MEDLINE
DCOM- 19950622
LR  - 20190614
IS  - 0006-8993 (Print)
IS  - 0006-8993 (Linking)
VI  - 672
IP  - 1-2
DP  - 1995 Feb 20
TI  - Long-term exposure to opioid antagonists up-regulates prodynorphin gene 
      expression in rat brain.
PG  - 42-7
AB  - We investigated the effect of long-term administration of opioid antagonists on 
      the regulation of prodynorphin gene expression in rat brain. 
      Intracerebroventricular (i.c.v.) injections for seven days of nor-binaltorphimine 
      (nor-BNI), the highly selective kappa opioid antagonist, naloxone and its longer 
      acting analog naltrexone, both relatively selective antagonists for the mu opioid 
      receptor, markedly raised prodynorphin mRNA levels in rat hypothalamus, 
      hippocampus and striatum. Peptides, namely immunoreactive-dynorphin A (ir-dyn A), 
      were unaffected after chronic treatment with all antagonists, in the same 
      tissues. These results, taken together with our previous observations, suggest 
      that chronic opioid antagonists, acting on kappa and mu opioid receptors, clearly 
      up-regulate prodynorphin gene expression in discrete rat brain regions, 
      activating its biosynthesis. Moreover, our data support the hypothesis that the 
      endogenous opioid system plays a role in the mechanisms underlying the 
      development of opiate tolerance.
FAU - Romualdi, P
AU  - Romualdi P
AD  - Department of Pharmacology, University of Bologna, Italy.
FAU - Lesa, G
AU  - Lesa G
FAU - Donatini, A
AU  - Donatini A
FAU - Ferri, S
AU  - Ferri S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Brain Res
JT  - Brain research
JID - 0045503
RN  - 0 (Enkephalins)
RN  - 0 (Narcotic Antagonists)
RN  - 0 (Protein Precursors)
RN  - 36B82AMQ7N (Naloxone)
RN  - 36OOQ86QM1 (norbinaltorphimine)
RN  - 5S6W795CQM (Naltrexone)
RN  - 93443-35-7 (preproenkephalin)
SB  - IM
MH  - Animals
MH  - Brain/*physiology
MH  - Enkephalins/*genetics
MH  - Gene Expression/*drug effects
MH  - Male
MH  - Naloxone/pharmacology
MH  - Naltrexone/analogs & derivatives/pharmacology
MH  - Narcotic Antagonists/*pharmacology
MH  - Protein Precursors/*genetics
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Time Factors
EDAT- 1995/02/20 00:00
MHDA- 1995/02/20 00:01
CRDT- 1995/02/20 00:00
PHST- 1995/02/20 00:00 [pubmed]
PHST- 1995/02/20 00:01 [medline]
PHST- 1995/02/20 00:00 [entrez]
AID - 0006-8993(94)01379-V [pii]
AID - 10.1016/0006-8993(94)01379-v [doi]
PST - ppublish
SO  - Brain Res. 1995 Feb 20;672(1-2):42-7. doi: 10.1016/0006-8993(94)01379-v.