Surprising Separation of Cannabinoid Physical Dependence and Withdrawal in an Invertebrate Model ()
Affiliation(s)
1Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania, USA.
2Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville FL, USA.
3Department of Pharmacology and Toxicology, University of Arizona College of Pharmacy, Tucson AZ, USA.
4Neumentum Inc., Palo Alto, CA, USA.
ABSTRACT
Planarians have mammalian-like neurotransmitter systems
and have been established as a novel in
vivo model for neuropharmacology. In previous research, planarians that
have been exposed to the cannabinoid receptor (CB-R) agonist WIN 55,212-2 for 1
h displayed abstinence-induced withdrawal when tested in drug-free, but not in
drug-containing, water. The goals of the present study were to extend previous
work and to further establish a cannabinoid behavioral model with planarians.
The results showed 1) four different CB-R antagonists (AM251, AM281, SLV319 and
SR144528) dose-relatedly blocked development of physical dependence induced by
two different CB-R agonists (WIN 55,212-2 and JWH251); 2) none of the same four antagonists (AM251, AM281, SLV319 or SR144528)
precipitated withdrawal; 3) short wavelength (254
nm), but not long wavelength (366 nm), ultraviolet (UV) light attenuated
abstinence-induced withdrawal from WIN 55,212-2, while short wavelength UV
light induced moderate withdrawal behavior. The results confirm the use of a
planarian model as a simple yet robust way to study development of physical
dependence to cannabinoid agonists. The effect of UV irradiation adds to the
evidence that the results are receptor-related. The results also give rise to
the surprising suggestion, within the limitations of the methodology, that
development of cannabinoid physical dependence and antagonist-induced
precipitated withdrawal might be separable phenomena in planarians.
Share and Cite:
Sheng, W. and Raffa, R. (2018) Surprising Separation of Cannabinoid Physical Dependence and Withdrawal in an Invertebrate Model.
Pharmacology & Pharmacy,
9, 489-502. doi:
10.4236/pp.2018.912038.
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