Cobalt Microinjections into the Infralimbic Cortex of the Anesthetized Rat Suppresses Circulatory and Respiratory Reactions to the Electrical Microstimulation of the Lateral Orbital Cortex

The central autonomic network that controls visceral systems,including circulatory and respiratory systems, includes the visceromotorinfralimbic cortex (IL), which is the prefrontal area located onthe medial surface of the cerebral hemispheres. At the same time,there is evidence that areas of the prefrontal cortex located onthe brain orbitofrontal surface, including the lateral orbital cortex(LO), can participate in the control of autonomic functions. Theaim of this study was to experimentally test the hypothesis accordingto which the participation of LO in the control of respiratory andcirculatory functions is realized through IL. To this end, in acuteexperiments on laboratory rats anesthetized with urethane, the effectof microinjections of cobalt chloride solution (CoCl₂)in IL on the reactions of circulatory and respiratory systems causedby electrical microstimulation of LO was investigated. It is knownthat Co²⁺ ions are non-specific blockersof synaptic transmission, therefore CoCl₂ microinjectionsdisrupt the interaction between CNS structures. In the first, controlseries of experiments, electrical microstimulation of LO causedspecific responses of the circulatory and respiratory systems, whichwere consistently reproduced throughout the experiment. In the second, experimentalseries, the microinjection of CoCl₂ solutioninto IL suppressed responses to electrical microstimulation of LO,and this effect turned out to be reversible. The obtained resultsconfirmed the hypothesis put forward about the possible participationof IL in the implementation of autonomic LO functions. The elucidationof the mechanisms that ensure the interaction of LO and IL in thecontext of autonomic control should be the subject of further experimentalresearch.