ABSTRACT
Striatal dopamine release is key for learning and motivation and is composed of subregions including the dorsal striatum (DS), nucleus accumbens core, and the nucleus accumbens shell. Spontaneously occurring dopamine release was compared across these subregions. Dopamine release/uptake dynamics differ across striatal subregions, with dopamine transient release amplitude and release frequency greatest in male mice, and the largest signals observed in the DS. Surprisingly, female mice exhibited little regional differences in dopamine release for DS and nucleus accumbens core regions, but lower release in the nucleus accumbens shell. Blocking voltage-gated K+ channel (Kv channels) with 4-aminopyridine enhanced dopamine detection without affecting reuptake. The 4-aminopyridine effects were greatest in ventral regions of female mice, suggesting regional differences in Kv channel expression. The dopamine transporter blocker cocaine also enhanced detection across subregions in both sexes, with greater overall increased release in females than males. Thus, sex differences in dopamine transmission are apparent and likely include differences in the Kv channel and dopamine transporter function. The lack of regional differences in dopamine release observed in females indicates differential regulation of spontaneous and evoked dopamine release.
Subject(s)
Cocaine , Dopamine , 4-Aminopyridine/metabolism , Animals , Cocaine/metabolism , Cocaine/pharmacology , Corpus Striatum/metabolism , Dopamine/metabolism , Dopamine Antagonists , Dopamine Plasma Membrane Transport Proteins/metabolism , Female , Male , Mice , Nucleus Accumbens/metabolism , Sex CharacteristicsABSTRACT
This investigation explored whether differences in cortical thickness could be detected in children who sustained a mild traumatic brain injury (mTBI) compared to those with orthopedic injury (OI) and whether cortical thickness related parental reporting of symptoms. To achieve this objective, FreeSurfer®-based cortical thickness measures were obtained in 330 children, 8 to 15â¯years of age, with either a history of mTBI or OI. Imaging was performed in all participants with the same 3 Tesla MRI scanner at six-months post-injury, where a parent-rated Post-Concussion Symptom Inventory (PCSI) was also obtained. Robust age-mediated reductions in cortical thickness were observed, but no consistent group-based differences between the mTBI and OI groups were observed. Also, the relation between mechanism of injury (i.e., sports-related, recreational, fall, motor vehicle accident or other) and cortical thickness was examined. Injuries associated with any type of abuse were excluded and children with OI could not have experienced a MVA. Mechanism of injury did not differentially relate to cortical thickness, although in the fall group, parental rating using the PCSI showed increased symptom reporting to be associated with reduced cortical thickness in the left interior frontal, temporal pole and lateral temporal lobe as well as in the right temporal pole. Results from these preliminary findings are discussed in terms of injury variables and developmental factors associated with mTBI in childhood.
