TY - JOUR
T1 - INTERMITTENT AND CHRONIC MORPHINE TREATMENT INDUCES LONG-LASTING CHANGES IN DELTA-OPIOID RECEPTOR-REGULATED ACETYLCHOLINE-RELEASE IN RAT STRIATUM AND NUCLEUS-ACCUMBENS
AU - TJON, GHK
AU - DEVRIES, TJ
AU - NESTBY, P
AU - WARDEH, G
AU - MULDER, AH
AU - SCHOFFELMEER, ANM
PY - 1995/9/5
Y1 - 1995/9/5
N2 - Intermittent treatment of rats with morphine (10 mg/kg s.c., once daily) caused an increase (of about 30%) of the electrically evoked release of [14C]acetylcholine from cholinergic interneurons of superfused striatal slices 1-21 days after morphine withdrawal. Similarly, chronic treatment with escalating doses of morphine (5-50 mg/kg s.c., 3 times daily), causing physical dependence (unlike intermittent treatment), resulted in an enduring enhanced response of these neurons towards depolarization. Following chronic morphine treatment this adaptive increase of acetylcholine release was associated with a slight but long-lasting decrease of the (δ-opioid receptor-mediated) maximal inhibitory effect of [Met5]enkephalin, whereas upon intermittent drug treatment δ-opioid receptor desensitization was observed 1 day after opiate withdrawal only. Also in slices of the nucleus accumbens both intermittent as well as chronic morphine administration caused a long-lasting increase of the electrically evoked [14C]acetylcholine release. Therefore, we hypothesize that an enhanced (re)activity of striatal and accumbal cholinergic neurons, which are regulated by dopaminergic neurons of the ventral mesencephalon, may represent a long-lasting neuroadaptive effect of morphine (and possibly other drugs of abuse) playing a crucial role in behavioral sensitization associated with enhanced vulnerability to drugs of abuse.
AB - Intermittent treatment of rats with morphine (10 mg/kg s.c., once daily) caused an increase (of about 30%) of the electrically evoked release of [14C]acetylcholine from cholinergic interneurons of superfused striatal slices 1-21 days after morphine withdrawal. Similarly, chronic treatment with escalating doses of morphine (5-50 mg/kg s.c., 3 times daily), causing physical dependence (unlike intermittent treatment), resulted in an enduring enhanced response of these neurons towards depolarization. Following chronic morphine treatment this adaptive increase of acetylcholine release was associated with a slight but long-lasting decrease of the (δ-opioid receptor-mediated) maximal inhibitory effect of [Met5]enkephalin, whereas upon intermittent drug treatment δ-opioid receptor desensitization was observed 1 day after opiate withdrawal only. Also in slices of the nucleus accumbens both intermittent as well as chronic morphine administration caused a long-lasting increase of the electrically evoked [14C]acetylcholine release. Therefore, we hypothesize that an enhanced (re)activity of striatal and accumbal cholinergic neurons, which are regulated by dopaminergic neurons of the ventral mesencephalon, may represent a long-lasting neuroadaptive effect of morphine (and possibly other drugs of abuse) playing a crucial role in behavioral sensitization associated with enhanced vulnerability to drugs of abuse.
KW - ACETYLCHOLINE RELEASE
KW - MORPHINE
KW - NUCLEUS ACCUMBENS
KW - OPIOID RECEPTOR
KW - SENSITIZATION
KW - STRIATUM
UR - http://www.scopus.com/inward/record.url?scp=0029155516&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/0014-2999(95)00319-G
DO - https://doi.org/10.1016/0014-2999(95)00319-G
M3 - Article
C2 - 7498306
SN - 0014-2999
VL - 283
SP - 169
EP - 176
JO - European journal of pharmacology
JF - European journal of pharmacology
IS - 1-3
ER -