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Beta-endorphin elevations in the ventral tegmental area regulate the discriminative effects of Delta-9-tetrahydrocannabinol.
Eur J Neurosci. 2004 Jun; 19(12):3183-92.EJ

Abstract

beta-Endorphin is an endogenous opioid that produces behavioral effects similar to heroin and morphine and is released in the nucleus accumbens by cocaine, amphetamine and ethanol, suggesting a general involvement in the reinforcing effects of abused drugs. Here we show that, in rats, Delta-9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, produces large increases in extracellular levels of beta-endorphin in the ventral tegmental area and lesser increases in the shell of the nucleus accumbens. We then used a two-lever choice THC-discrimination procedure to investigate whether THC-induced changes in endogenous levels of beta-endorphin regulate the discriminative effects of THC. In rats that had learned to discriminate injections of THC from injections of vehicle, the opioid agonist morphine did not produce THC-like discriminative effects but markedly potentiated discrimination of THC. Conversely, the opioid antagonist naloxone reduced the discriminative effects of THC. Bilateral microinjections of beta-endorphin directly into the ventral tegmental area, but not into the shell of the nucleus accumbens, markedly potentiated the discriminative effects of ineffective threshold doses of THC but had no effect when given alone. This potentiation was blocked by naloxone. Together these results indicate that certain psychotropic effects of THC related to drug abuse liability are regulated by THC-induced elevations in extracellular beta-endorphin levels in brain areas involved in opiate reward and reinforcement processes.

Authors+Show Affiliations

Preclinical Pharmacology Section, Department of Health and Human Services, National Institutes of Health, National Institute on Drug Abuse, Baltimore, MD 21224, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15217374

Citation

Solinas, M, et al. "Beta-endorphin Elevations in the Ventral Tegmental Area Regulate the Discriminative Effects of Delta-9-tetrahydrocannabinol." The European Journal of Neuroscience, vol. 19, no. 12, 2004, pp. 3183-92.
Solinas M, Zangen A, Thiriet N, et al. Beta-endorphin elevations in the ventral tegmental area regulate the discriminative effects of Delta-9-tetrahydrocannabinol. Eur J Neurosci. 2004;19(12):3183-92.
Solinas, M., Zangen, A., Thiriet, N., & Goldberg, S. R. (2004). Beta-endorphin elevations in the ventral tegmental area regulate the discriminative effects of Delta-9-tetrahydrocannabinol. The European Journal of Neuroscience, 19(12), 3183-92.
Solinas M, et al. Beta-endorphin Elevations in the Ventral Tegmental Area Regulate the Discriminative Effects of Delta-9-tetrahydrocannabinol. Eur J Neurosci. 2004;19(12):3183-92. PubMed PMID: 15217374.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Beta-endorphin elevations in the ventral tegmental area regulate the discriminative effects of Delta-9-tetrahydrocannabinol. AU - Solinas,M, AU - Zangen,A, AU - Thiriet,N, AU - Goldberg,S R, PY - 2004/6/26/pubmed PY - 2004/8/19/medline PY - 2004/6/26/entrez SP - 3183 EP - 92 JF - The European journal of neuroscience JO - Eur J Neurosci VL - 19 IS - 12 N2 - beta-Endorphin is an endogenous opioid that produces behavioral effects similar to heroin and morphine and is released in the nucleus accumbens by cocaine, amphetamine and ethanol, suggesting a general involvement in the reinforcing effects of abused drugs. Here we show that, in rats, Delta-9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, produces large increases in extracellular levels of beta-endorphin in the ventral tegmental area and lesser increases in the shell of the nucleus accumbens. We then used a two-lever choice THC-discrimination procedure to investigate whether THC-induced changes in endogenous levels of beta-endorphin regulate the discriminative effects of THC. In rats that had learned to discriminate injections of THC from injections of vehicle, the opioid agonist morphine did not produce THC-like discriminative effects but markedly potentiated discrimination of THC. Conversely, the opioid antagonist naloxone reduced the discriminative effects of THC. Bilateral microinjections of beta-endorphin directly into the ventral tegmental area, but not into the shell of the nucleus accumbens, markedly potentiated the discriminative effects of ineffective threshold doses of THC but had no effect when given alone. This potentiation was blocked by naloxone. Together these results indicate that certain psychotropic effects of THC related to drug abuse liability are regulated by THC-induced elevations in extracellular beta-endorphin levels in brain areas involved in opiate reward and reinforcement processes. SN - 0953-816X UR - https://www.unboundmedicine.com/medline/citation/15217374/Beta_endorphin_elevations_in_the_ventral_tegmental_area_regulate_the_discriminative_effects_of_Delta_9_tetrahydrocannabinol_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0953-816X&date=2004&volume=19&issue=12&spage=3183 DB - PRIME DP - Unbound Medicine ER -