caa a22 4500 477074073 CHVBK 20180405111434.0 cr unu---uuuuu 170330e19960101xx s 000 0 eng 10.1007/BF02252563 doi (NATIONALLICENCE)springer-10.1007/BF02252563 Participation of the opioid- and serotonergic systems of the ventrolateral medullary regions in the control of respiratory activity in early postnatal rats [Elektronische Daten] [V. Marchenko, V. Fenik, N. Preobrazhenskii, M. Seredenko] The effects of blockers of opioid and serotonin receptors (naloxone and methisergide, respectively) on the respiratory activity recorded from then. phrenicus of semi-isolated medullo-spinal preparations (SIMSP) were studied in newborn (1-day-old) and 4- to 5-day-old rats. The preparations were superfusedin situ, and inspiratory discharges (ID) were recorded before and after transverse sections of the ventrolateral medullary regions (VLMR) at different levels. Naloxone evoked an increase in the ID frequency in then. phrenicus both at the initial configuration of preparations and after successive transections of the VLMR between theM andS chemosensitive zones and between theS andL zones. The relative intensity of this effect was significantly higher in newborn rats than in 4- to 5-day-old ones. In contrast, methisergide made the ID frequency lower at all configurations of the SIMSP, and this effect was more intensive in 4- to 5-day-old animals. In the course of progressive separations of more rostral VLMR zones, the effects of naloxone and methisergide applications on the ID frequency became weaker. This allows us to suppose that in newborn rats the rostral VLMR portions provide more intensive opioidergic inhibitory control influences on the activity of respiratory networks than those in 4- to 5-day-old animals. At the same time, tonic activating influences from serotonergic VLMR neurons on the mechanisms generating respiratory rhythm are more intensive in 4- to 5-day-old animals than those in newborn ones. Thus, it can be supposed that the levels of maturation of the opioid- and serotonergic neurotransmitter systems, which provide tonic control of respiratory activity generated in the VLMR, are different in newborn and 4- to 5-day-old animals. The problems of how the opioid- and serotonergic mechanisms controlling respiratory rhythm generation are formed in the course of early stages of ontogenetic development are discussed. Plenum Publishing Corporation, 1997 Marchenko V. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut Fenik V. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut Preobrazhenskii N. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut Seredenko M. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut Neurophysiology Kluwer Academic Publishers-Plenum Publishers 28/1(1996-01-01), 49-58 0090-2977 28:1<49 1996 28 11062 https://doi.org/10.1007/BF02252563 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02252563 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Marchenko V. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut NATIONALLICENCE 700 1- Fenik V. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut NATIONALLICENCE 700 1- Preobrazhenskii N. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut NATIONALLICENCE 700 1- Seredenko M. Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine aut NATIONALLICENCE 773 0- Neurophysiology Kluwer Academic Publishers-Plenum Publishers 28/1(1996-01-01), 49-58 0090-2977 28:1<49 1996 28 11062 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer