PMID- 6889535
OWN - NLM
STAT- MEDLINE
DCOM- 19821202
LR  - 20190624
IS  - 0014-2999 (Print)
IS  - 0014-2999 (Linking)
VI  - 81
IP  - 2
DP  - 1982 Jul 9
TI  - Electroconvulsive shock (ECS) and H-endorphin-induced analgesia: unconventional 
      interactions with naloxone.
PG  - 237-43
AB  - Acute administration of electroconvulsive shock (ECS) has been shown previously 
      to produce potent analgesia which is only partially reversed by naloxone but 
      shows almost complete tolerance after both repeated ECS and chronic morphine 
      administration. In an attempt to elucidate the underlying basis of ECS analgesia 
      it was recently compared with the analgesic effect of a newly identified opioid, 
      humoral (H)-endorphin. Intracerebroventricular (i.c.v.) injection of H-endorphin 
      to rats produces a dose-related analgesic effect as measured by the tail flick 
      method. Furthermore, 4 days of daily i.c.v. injections of 40 microgram of 
      morphine resulted in complete tolerance to the analgesic effect of H-endorphin. 
      However, naloxone only caused a partial reversal of H-endorphin analgesia. 
      Surprisingly only the lower dose of 1 mg/kg exerted a significant antagonistic 
      effect while a higher dose of 10 mg/kg of the antagonist was without effect. A 
      similar unconventional profile of the effect of naloxone could be seen with ECS 
      analgesia. Here, pretreatment with 1 mg/kg of naloxone significantly attenuated 
      analgesia, whereas administration of 10 mg/kg of the antagonist was without 
      effect. In contrast, catalepsy measured in the same animals was not affected by 1 
      mg/kg of naloxone but increasing the dose to 10 mg/kg produced a significant 
      attenuation of ECS catalepsy. The opioid nature of H-endorphin analgesia on one 
      hand and the unconventional dose relation with naloxone of both H-endorphin and 
      ECS analgesia on the other hand, suggests the involvement of this opioid in 
      analgesia induced by ECS. Furthermore, it is possible that other behavioral 
      manipulations which display only partial opiate characteristics may be mediated 
      by H-endorphin or similar endogenous substances.
FAU - Urca, G
AU  - Urca G
FAU - Harouni, A
AU  - Harouni A
FAU - Sarne, Y
AU  - Sarne Y
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Eur J Pharmacol
JT  - European journal of pharmacology
JID - 1254354
RN  - 0 (Endorphins)
RN  - 36B82AMQ7N (Naloxone)
RN  - 76I7G6D29C (Morphine)
RN  - 77030-45-6 (endorphin, humoral)
SB  - IM
MH  - *Analgesia
MH  - Animals
MH  - Catalepsy/prevention & control
MH  - Dose-Response Relationship, Drug
MH  - Drug Tolerance
MH  - *Electroshock
MH  - Endorphins/*antagonists & inhibitors/pharmacology
MH  - Humans
MH  - Male
MH  - Morphine/pharmacology
MH  - Naloxone/*pharmacology
MH  - Rats
EDAT- 1982/07/09 00:00
MHDA- 1982/07/09 00:01
CRDT- 1982/07/09 00:00
PHST- 1982/07/09 00:00 [pubmed]
PHST- 1982/07/09 00:01 [medline]
PHST- 1982/07/09 00:00 [entrez]
AID - 0014-2999(82)90441-1 [pii]
AID - 10.1016/0014-2999(82)90441-1 [doi]
PST - ppublish
SO  - Eur J Pharmacol. 1982 Jul 9;81(2):237-43. doi: 10.1016/0014-2999(82)90441-1.