[Role of the lateroventral periolivary nucleus in the central chemoreception of respiration in rats].

Using the methods of microinjection, microiontophoresis, electrolytic destruction and electric stimulation, the present work was undertaken to investigate whether the lateroventral periolivary nucleus (LVPO) might play a role in the central mechanism of chemoreception on respiration. Experiments were performed on 38 chloralose-urethane anesthetized Sprague-Dawley rats. The results were as follows: (1) Bilateral microinjection of acidified mock CSF into the LVPO region, evoked an enhancement in respiratory activities. (2) Microiontophoretic application of H+ caused mainly excitatory effects on the spontaneously discharging units in LVPO region, and some of the excitatory units were also responsible to microinjection of acidified mock CSF to the ventrolateral medullary surface. (3) After the electrolytic destruction of bilateral LVPO region in carotid body denervated rats, respiratory response to inhaled CO2 was attenuated significantly. (4) Electric stimulation of LVPO region caused an increase in discharging frequency of some units in the NTS and NRA regions. The above results indicate that LVPO plays a significant role in the central mechanism of chemoreception.