Investigation of calcium-stimulated adenylyl cyclases 1 and 8 on toluene and ethanol neurobehavioral actions ☆ Alana C. Conti a, b, ⁎, Jennifer L. Lowing a, b , Laura L. Susick a, b , Scott E. Bowen c, d a John D. Dingell VA Medical Center, 4646 John R St. (11R), Detroit, MI 48201, USA b Department of Neurosurgery Wayne State University, VAMC, 4646 John R. St. (11R), Detroit, MI 48201, USA c Department of Psychology, Wayne State University, 5057 Woodward Ave., Detroit, MI 48202, USA d Department of Obstetrics & Gynecology, Wayne State University, 5057 Woodward Ave., Detroit, MI 48202, USA abstract article info Article history: Received 22 December 2011 Received in revised form 25 June 2012 Accepted 29 June 2012 Available online 10 July 2012 Keywords: Toluene Adenylyl cyclase Ethanol Calcium Locomotor The abused inhalant toluene has potent behavioral effects, but only recently has progress been made in understanding the molecular pathways that mediate the action of toluene in the brain. Toluene and ethanol induce similar behavioral effects and share some targets including NMDA and GABA receptors. In studies examining neuronal actions of ethanol, mice lacking the calcium-stimulated adenylyl cyclases (ACs), AC1 and AC8 (DKO), show increased sedation durations and impaired protein kinase A (PKA) phosphorylation following acute ethanol treatment. Therefore, using DKO mice, we compared the neurobehavioral responses following toluene exposure to that of ethanol exposure to determine if these abused substances share molec- ular mechanisms of action. In the present study, acute sensitivity to toluene- or ethanol-induced changes in locomotor activity was evaluated in DKO and wild type (WT) mice. Mice were exposed to toluene vapor (0, 500, 1000, 2000, 6000, or 8000 ppm) for 30 min in static exposure chambers equipped with activity moni- tors. Both WT and DKO mice demonstrated increased ambulatory distance during exposure to a 2000-ppm concentration of toluene compared to respective air-exposed (0 ppm) controls. Significant increases in loco- motor activity were also observed during an air-only recovery period following toluene exposure in WT and DKO mice that had been exposed to 2000 ppm of toluene compared to respective air controls. Sedative ef- fects of toluene were equivalent in WT and DKO mice, both during exposure and afterwards during recovery. Although no significant differences in locomotor activity were detected in DKO compared to WT mice at in- dividual doses tested, a significant main effect of toluene was achieved, with DKO mice demonstrating a gen- eralized reduction in locomotor activity during the post-toluene recovery period compared to WT mice (when analyzing all doses collectively). For comparison to toluene, additional WT and DKO mice were treated with 1.0 or 2.0 g/kg ethanol (i.p.) and monitored for locomotor activation. In WT mice, both doses of ethanol increased distance traveled compared to saline controls. Conversely, DKO mice demonstrated no increase in locomotor activation at 1.0 g/kg, with significantly reduced distances traveled at both doses compared to ethanol-treated WT mice. These behavioral activity results suggest that acute effects of ethanol and toluene are distinct in the mechanisms by which they induce acute sedating effects with respect to AC1 and AC8 ac- tivity, but may be similar in the mechanisms subserving locomotor stimulation. © 2012 Elsevier Inc. All rights reserved. 1. Introduction Toluene is a widely used industrial solvent that is also deliberately inhaled for its euphoric and intoxicating effects (Cruz and Bowen, 2008; Howard et al., 2011). Found in adhesives, paint and cleaning fluids, toluene is readily available, inexpensive and legal to obtain, making it a popular inhalant among adolescents. The most recent Monitoring the Future survey revealed that lifetime prevalence of vol- atile substance misuse among 8th graders is 14.9%, higher than all other illicit drugs in this age group with the exception of marijuana (15.7%) (Johnston et al., 2010). A recent National Survey on Drug Use and Health (SAMHSA) indicates that more than 22 million Amer- icans have intentionally misused volatile substances at least once in Neurotoxicology and Teratology 34 (2012) 481–488 ☆ This work was supported by WSU Start Up Funds (ACC) and WSU Bridge Funding (SEB). These sources had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication. Preliminary reports of a portion of this study were presented at the 73rd Annual Meeting of the College on Problems of Drug Depen- dence, Hollywood, FL, June, 2011. ⁎ Corresponding author at: John D. Dingell VA Medical Center, 4646 John R. St. (11R), Detroit, MI 48201, USA. Tel.: +1 313 576 3311; fax: +1 313 576 1112. E-mail addresses: aconti@med.wayne.edu (A.C. Conti), jlowing@med.wayne.edu (J.L. Lowing), lsusick@med.wayne.edu (L.L. Susick), scott.bowen@wayne.edu (S.E. Bowen). 0892-0362/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.ntt.2012.06.005 Contents lists available at SciVerse ScienceDirect Neurotoxicology and Teratology journal homepage: www.elsevier.com/locate/neutera