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Efferent projections of ventral respiratory group of the rat
79 et al., Neurochem. Int., 21 p. C4, 1992a.] (This work was supported by grants from MURST and CNR.)
59 NGF Can Reverse Age-changes in the Pattern and Density of Reinnervation of Transplanted Cerebral Blood Vessels from Ageing Rats Isabella Gavazzi and Timothy Cowen
Department of Anatomy and Developmental Biology, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2PF, UK We have shown previously that middle cerebral arteries from young and old rats transplanted in oculo in young hosts become reinnervated with a density and pattern of innervation that is typical of the age of the donor, i.e., the density of reinnervation on old transplants is 50% lower than on young transplants. The alterations in the target tissues responsible for their decreased innervation in old age are still unknown. We have investigated the possibility that increasing the availability of nerve growth factor (NGF) might restore the pattern and density of perivascular nerves on old transplanted blood vessels to levels of innervation typical of young tissues. Old middle cerebral transplants were therefore treated with N G F or vehicle using 3 weekly, transcleral injections. Control experiments were performed treating transplants with saline, bovine serum albumin or cytochrome c. Young middle cerebral transplants were exposed to the same treatment for comparison. N G F treatment markedly increased reinnervation of old transplants, restoring the density and pattern of innervation to one characteristic of young animals. N G F produced an equivalent increase in nerve growth on young and old transplants, confirming that the receptivity of old blood vessels to reinnervation is not impaired.
6O Efferent Projections of Ventral Respiratory Group of the Rat S.P. Gaytfin-Gula, A.M. Morillo and R. Pfisaro
Department of Animal Physiology and Biology, University of Sevilla, 41012-Sevilla, Spain The trajectories of axonal projections from propriobuibar and bulbospinal neurons of the Ventral Respiratory Group were anterogradely labelled after discrete injections of Fluoro Ruby into one of the three physiologically identified subdivisions (B6tzinger complex, rostral inspiratory and caudal expiratory regions). The efferent projections from these regions were found throughout the
rostrocaudal extent of the medulla and the pons, terminating in a variety of areas known to have cardiorespiratory function. Anterograde labelling was located within other subdivisions of Ventral Respiratory Group, Ventrolateral Medulla, parabrachialis nuclei (medial, externolateral and central lateral), K611iker-Fuse nucleus, retrotrapezoid nucleus, lateral paragigantocellularis nucleus and lateral tegmental field of the pons. Axons bundles were organized as two compact masses, running along each ventrolateral medulla and pons, along its rostro-caudal axis. Both bundles were connected by crossing efferent projections which provided the other side of the medulla. By collateral branching of these ventrolateral bundles, there were another two types of projection; towards the solitary tract nucleus where they make a turn and addressed towards the other side of the medulla, and towards the parabrachialis nucleus. This complex axonal efferent network provides a unique framework for future electrophysiological studies of the interconnections between cardio-respiratory neurons.
61 Multiple Sequential Spectral Analysis (MSSA): a New Approach to R-R Variability Spectral Analysis G. Gigli 1, G. Reggiardo 2, M. Casu 1, M. Perocchio l, M. Iannetti I and S. Parodi 2
~Servizio di Cardiologia-UTIC, Ospedale di Rapallo, P. Molfino 10, 16035, Rapallo (Ge) and 2Servizio di Epidemiologia Ambientale e Biostatistica, IST, Genova, Italy Spectral analysis of R-R variability is a useful method for evaluation of sympathovagal interaction modulating cardiovascular function. It presents, however, some unresolved questions, like the position and the length of tachogram segments to be analyzed and the correction for extrabeats. As to these problems, we propose a software that, by MEM method, performs consecutive analysis of short (64 beats) subsequent (one point step) segments of tachogram and allows correction for extrabeats. Using a Maximum Partial Ratio Likelihood method, a power spectrum density is then extrapolated representing all obtained functions with a 0.05 significance (95% C.I.). The final output provides the frequency and power values of each spectral component. Extrabeats appearing in the original tachogram can be automatically corrected replacing with the value of best probability calculated by statistical analysis of the function identified by the previous and the following 10 points. By this method we performed spectral analysis of R-R variability in 16 young normal subjects (9 men and 7 women, mean age 31 + 6.4 years). In all subjects we were able to identify the two classical components, one centered at a frequency
59 NGF Can Reverse Age-changes in the Pattern and Density of Reinnervation of Transplanted Cerebral Blood Vessels from Ageing Rats Isabella Gavazzi and Timothy Cowen
Department of Anatomy and Developmental Biology, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2PF, UK We have shown previously that middle cerebral arteries from young and old rats transplanted in oculo in young hosts become reinnervated with a density and pattern of innervation that is typical of the age of the donor, i.e., the density of reinnervation on old transplants is 50% lower than on young transplants. The alterations in the target tissues responsible for their decreased innervation in old age are still unknown. We have investigated the possibility that increasing the availability of nerve growth factor (NGF) might restore the pattern and density of perivascular nerves on old transplanted blood vessels to levels of innervation typical of young tissues. Old middle cerebral transplants were therefore treated with N G F or vehicle using 3 weekly, transcleral injections. Control experiments were performed treating transplants with saline, bovine serum albumin or cytochrome c. Young middle cerebral transplants were exposed to the same treatment for comparison. N G F treatment markedly increased reinnervation of old transplants, restoring the density and pattern of innervation to one characteristic of young animals. N G F produced an equivalent increase in nerve growth on young and old transplants, confirming that the receptivity of old blood vessels to reinnervation is not impaired.
6O Efferent Projections of Ventral Respiratory Group of the Rat S.P. Gaytfin-Gula, A.M. Morillo and R. Pfisaro
Department of Animal Physiology and Biology, University of Sevilla, 41012-Sevilla, Spain The trajectories of axonal projections from propriobuibar and bulbospinal neurons of the Ventral Respiratory Group were anterogradely labelled after discrete injections of Fluoro Ruby into one of the three physiologically identified subdivisions (B6tzinger complex, rostral inspiratory and caudal expiratory regions). The efferent projections from these regions were found throughout the
rostrocaudal extent of the medulla and the pons, terminating in a variety of areas known to have cardiorespiratory function. Anterograde labelling was located within other subdivisions of Ventral Respiratory Group, Ventrolateral Medulla, parabrachialis nuclei (medial, externolateral and central lateral), K611iker-Fuse nucleus, retrotrapezoid nucleus, lateral paragigantocellularis nucleus and lateral tegmental field of the pons. Axons bundles were organized as two compact masses, running along each ventrolateral medulla and pons, along its rostro-caudal axis. Both bundles were connected by crossing efferent projections which provided the other side of the medulla. By collateral branching of these ventrolateral bundles, there were another two types of projection; towards the solitary tract nucleus where they make a turn and addressed towards the other side of the medulla, and towards the parabrachialis nucleus. This complex axonal efferent network provides a unique framework for future electrophysiological studies of the interconnections between cardio-respiratory neurons.
61 Multiple Sequential Spectral Analysis (MSSA): a New Approach to R-R Variability Spectral Analysis G. Gigli 1, G. Reggiardo 2, M. Casu 1, M. Perocchio l, M. Iannetti I and S. Parodi 2
~Servizio di Cardiologia-UTIC, Ospedale di Rapallo, P. Molfino 10, 16035, Rapallo (Ge) and 2Servizio di Epidemiologia Ambientale e Biostatistica, IST, Genova, Italy Spectral analysis of R-R variability is a useful method for evaluation of sympathovagal interaction modulating cardiovascular function. It presents, however, some unresolved questions, like the position and the length of tachogram segments to be analyzed and the correction for extrabeats. As to these problems, we propose a software that, by MEM method, performs consecutive analysis of short (64 beats) subsequent (one point step) segments of tachogram and allows correction for extrabeats. Using a Maximum Partial Ratio Likelihood method, a power spectrum density is then extrapolated representing all obtained functions with a 0.05 significance (95% C.I.). The final output provides the frequency and power values of each spectral component. Extrabeats appearing in the original tachogram can be automatically corrected replacing with the value of best probability calculated by statistical analysis of the function identified by the previous and the following 10 points. By this method we performed spectral analysis of R-R variability in 16 young normal subjects (9 men and 7 women, mean age 31 + 6.4 years). In all subjects we were able to identify the two classical components, one centered at a frequency