Assessing the Value of the Zebrafish Conditioned Place Preference Model for Predicting Human Abuse Potential

Abstract

Regulatory agencies recommend that centrally active drugs are tested for abuse potential before approval. Standard preclinical assessments are conducted in rats or non-human primates (NHPs). This study evaluated the ability of the zebrafish conditioned place preference (CPP) model to predict human abuse outcomes. Twenty-seven compounds from a variety of pharmacological classes were tested in zebrafish CPP, categorized as positive or negative, and analyzed using standard diagnostic tests of binary classification to determine the likelihood that zebrafish correctly predict robust positive signals in human subjective effects studies (+HSE) and/or Drug Enforcement Administration drug scheduling. Results were then compared with those generated for rat self-administration and CPP, as well as NHP self-administration, using this same set of compounds. The findings reveal that zebrafish concordance and sensitivity values were not significantly different from chance for both +HSE and scheduling. Although significant improvements in specificity and negative predictive values were observed for zebrafish relative to +HSE, specificity without sensitivity provides limited predictive value. Moreover, assessments in zebrafish provided no added value for predicting scheduling. By contrast, rat and NHP models generally possessed significantly improved concordance, sensitivity, and positive predictive values for both clinical measures. Although there may be predictive value with compounds from specific pharmacological classes (e.g., -opioid receptor agonists, psychostimulants) for zebrafish CPP, altogether these data highlight that using the current methodology, the zebrafish CPP model does not add value to the preclinical assessment of abuse potential.

Identification ofSlit3as a locus affecting nicotine preference in zebrafish and human smoking behaviour

“…Zebrafish express the same set of neuronal 37 nicotinic acetylcholine receptors as found in other vertebrates (α2, α3, α4, α6, α7, α8, 38 β2, β3, β4) (15,16) with similar binding characteristics (17,18). Zebrafish show robust 39 CPP to nicotine (18)(19)(20)(21) and nicotinic receptor partial agonists that modulate striatal 40 dopamine release in response to nicotine in mammalian systems also inhibit nicotine-41 induced CPP in zebrafish (18). Further, on prolonged exposure to nicotine or ethanol, 42 adult zebrafish show conserved adaptive changes in gene expression and develop 43 dependence-related behaviours, such as persistent drug seeking despite adverse 44 stimuli or reinstatement of drug seeking following periods of abstinence (21).…”

“…We selected a nicotine concentration predicted to induce a minimal detectable CPP in 100 wildtypes (5µM) (19,20), to enable us to detect both increased and decreased response 101 to nicotine in mutants. To ensure that this strategy could detect genetic factors 102 affecting response to nicotine, we assessed the heritability of the CPP response in 103 ENU mutagenized fish using a selective breeding approach over three generations.…”

“…This minimal effective dose was used to avoid possible ceiling effects if using a 472 higher concentration. CPP was assessed as described previously (19,20,59): The 473 testing apparatus was an opaque 3 L rectangular tank that could be divided in half 474 with a Perspex divider. Each end of the tank had distinct visual cues (1.5cm diameter 475 black spots versus vertical 0.5cm wide black and white stripes, matched for 476 luminosity).…”

“…The change in place 489 preference was determined as the proportion time spent in the nicotine-paired zone 490 during the probe trial minus the proportion time spent in the nicotine-paired zone 491 during basal testing. The CPP procedure has been used and validated previously with 492 nicotine as well as other drugs (19,20,59) . 493 494 Data analysis: Change in preference scores were calculated as proportion time spent 495 in drug paired stimulus after conditioning minus proportion time spent in drug paired 496 stimulus before conditioning.…”

Reporting animal research: Explanation and Elaboration for the ARRIVE guidelines 2019

“…The conditioning tank consisted of an opaque tank measuring 20 cm (w) 15 cm (h) 30 cm (l) containing 2.5 l of aquarium water with distinct visual cues (spots or stripes) on walls at each end of the tank… During habituation, each individual fish was placed in the conditioning apparatus for 20 minutes with free access to both compartments and then returned to its home tank." [135] 9d. Why (provide rationale for procedures).…”