The brain networks connected to the sympathetic motor and sensory innervations of brown (BAT) and white (WAT) adipose tissues were originally described using two transneuronally transported viruses: the retrogradely transported pseudorabies virus (PRV), and the anterogradely transported H129 strain of herpes simplex virus-1 (HSV-1 H129). Further complexity was added to this network organization when combined injections of PRV and HSV-1 H129 into either BAT or WAT of the same animal generated sets of co-infected neurons in the brain, spinal cord, sympathetic and dorsal root ganglia. These neurons are well positioned to act as sensorimotor links in the feedback circuits that control each fat pat. We have now determined the extent of sensorimotor crosstalk between inguinal (I)BAT and IWAT. PRV152 and HSV-1 H129 were each injected into IBAT or IWAT of the same animal: H129 into IBAT and PRV152 into IWAT. The reverse configuration was applied in a different set of animals. We found single labeled neurons together with H129+PRV152 co-infected neurons in multiple forebrain, midbrain, and hindbrain sites, with lesser numbers in the sympathetic and dorsal root ganglia that innervate IBAT and IWAT. We propose that these co-infected neurons mediate sensory-sympathetic motor crosstalk between IBAT and IWAT. Comparing the relative numbers of co-infected neurons between the two injection configurations showed a bias towards IBAT-sensory and IWAT-sympathetic motor feedback loops. These co-infected neurons provide a neuroanatomical framework for functional interactions between IBAT thermogenesis and IWAT lipolysis that occurs with cold exposure, food restriction/deprivation, exercise, and more generally with alterations in adiposity.
- Herpes simplex virus
- pseudorabies virus
- Siberian hamsters
- Copyright © 2015, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology