Naloxone-reversible effects of d-Ala2-Met5-enkephalinamide-induced behavioral activity in rats

Harston, Craig T.; Spirtes, Morris A.; Dunlap, William P.; Coy, David H.

doi:10.1016/s0163-1047(80)90824-9

Cited by 16 publications

(3 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conversely, naloxone suppressed feeding and spontaneous locomotion. Similar suppressive effects of naloxone on exploratory activity were reported in rats (FILE, 1980;HARTSON et al, 1980). An acute or chronic administration of an opiate antagonist, naloxone or naltrexone, via a central on peripheral route suppresses feeding activity (COOPER, 1980;LowY et a!.,1980;JONES and RICHTER, 1981;CLARKSON et al, 1982;LANG et al, 1982).…”

supporting

confidence: 66%

“…The increase seemed to be mainly attributable to the increased WR before and after the feeding time. FILE (1980) and HARTSON et al (1980) reported that the exploratory activity which may sometimes be linked to food searching behavior was suppressed by an opiate antagonist, naloxone, in rats. We had, therefore, assumed that the endogenous opioid system may participate in the development of the anticipatory locomotor activity (fraction D).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of chronic administration of naloxone on wheel running activity in rats under 2-h feeding schedule.

1986

View full text Add to dashboard Cite

The effects of chronic administration of naloxone (120-150,ig•kg-1 •h-1) on the wheel running activity (WR) and on food and water intakes were studied in male Wistar rats subjected to a 2-h restricted feeding (1200-1400 h) schedule at 24 ± 1°C and LD 12: 12 (L: 0600-1800 h) cycle. The restricted feeding significantly increased WR before and after the feeding time. Food and water intakes per day were reduced and body weight gradually decreased for the 2-week food restriction period. Food and water intakes appeared to be suppressed by naloxone, particularly shortly after the administration. The chronically administered naloxone slightly increased the 24-h WR. In the naloxone-treated rats, the fraction of WR before the feeding time (anticipatory activity) was significantly increased compared with saline-treated rats. The fraction of WR after the feeding time (succeeding activity) did not change. These results suggest that the endogenous opioid system may play a role in suppressing the excess increase in the anticipatory locomotor activity in the food restricted rats.

show abstract

supporting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Effects of chronic administration of naloxone on wheel running activity in rats under 2-h feeding schedule.

1986

View full text Add to dashboard Cite

show abstract

“…The opiate antagonist naloxone inhibits locomotor activity and exploration in the rat (altair et al, 1979;Walker et al,, 1981), while morphine and enkephalin, after an initial depressing effect, stimulate these activities (Harston et al, 1980). Moreover, direct injection of d-ala2-metS-enkephalin-amide into the ventral tegmental area or the nucleus accumbens have been shown to increase locomotor activity in a dose-dependent way (Broekkamp et al, 1979;Pert and Sivit, 1977).…”

Section: Introductionmentioning

confidence: 99%

Interactions between naloxone and GABA in the control of locomotor activity in the rat

Ågmo

Tarasco

1985

J. Neural Transmission

View full text Add to dashboard Cite

It was found that naloxone causes a small but significant reduction of motility. The GABAB agonist baclofen and the GABA transaminase inhibitor gamma-acetylenic GABA (GAG) also reduced locomotor activity. When a subeffective dose of baclofen was combined with naloxone 0.8 or 3.2 mg/kg, baclofen significantly inhibited motility beyond the inhibition caused by naloxone + saline. GAG, in a dose of 12.5 mg/kg, was also potentiated by naloxone, 3.2 mg/kg. The locomotion reducing effects of naloxone could be blocked by either picrotoxin or bicuculline. It is concluded that GABAergic mechanisms participate in the inhibition of locomotor activity provoked by naloxone. The possibility that this drug disinhibits GABAergic neurons is discussed.

show abstract

Inhibitory effect of opiates on male rat sexual behavior may be mediated by opiate receptors outside the central nervous system

Ågmo

Vázquez

1992

Psychopharmacology

View full text Add to dashboard Cite

The importance of opiate receptors outside the central nervous system for the inhibitory actions of morphine on male rat sexual behavior was evaluated. Morphine (10 mg/kg) produced an almost complete inhibition of sexual behavior. This inhibition was antagonized by naloxone at a dose of 1 mg/kg but not at a dose of 0.25 mg/kg. The quaternary opioid antagonist methylnaloxone effectively blocked the inhibitory actions of morphine at a dose of 20 mg/kg but not at a dose of 5 mg/kg. Since the affinity of methylnaloxone for opiate receptors is about 5% of that of naloxone, it may be concluded that both antagonists were about equally effective in inhibiting the effects of morphine. Furthermore, the opiate-like drug loperamide was found to inhibit sexual behavior. This drug acts mainly outside the central nervous system. Its effect was blocked by both naloxone and methylnaloxone, suggesting that opiate receptors are involved. It was also shown that methylnaloxone is unable to block the reinforcing effects of morphine in the conditioned place preference procedure. Because the reinforcing effects of opiates seem to be localized to the central nervous system, it may be proposed that methylnaloxone does not antagonize morphine's central effects. Moreover, loperamide had no effect in the place preference procedure, suggesting that this drug does not act at central opioid receptors. Taken together, these data show that peripheral opioid receptors are responsible for at least some of the inhibitory actions of morphine on male sexual behavior. After treatment with morphine + methylnaloxone, ejaculatory mechanisms were facilitated, reflected in a reduced number of preejaculatory intromissions and a shortened ejaculation latency.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

Naloxone-reversible effects of d-Ala2-Met5-enkephalinamide-induced behavioral activity in rats

Cited by 16 publications

References 39 publications

Effects of chronic administration of naloxone on wheel running activity in rats under 2-h feeding schedule.

Effects of chronic administration of naloxone on wheel running activity in rats under 2-h feeding schedule.

Interactions between naloxone and GABA in the control of locomotor activity in the rat

Inhibitory effect of opiates on male rat sexual behavior may be mediated by opiate receptors outside the central nervous system

Contact Info

Product

Resources

About