title: Phrenic responses to contralateral spinal stimulation in rats: effects of old age or chronic spinal hemisection.
abstract: Serotonin reveals ineffective spinal pathways from the C2-lateral funiculus to contralateral phrenic motoneurons in young adult rats with acute spinal hemisection. We tested the hypothesis that old age (1.5-2 years) or chronic hemisection (3-5 days) strengthens these pre-existing crossed spinal pathways. There were no consistent differences between young adult rats with acute hemisection versus young adult rats with chronic hemisection or old rat with acute hemisection except that one long-latency phrenic excitation could not be elicited in old rats. The results indicate that neither old age nor chronic hemisection strengthens crossed-spinal pathways, but that old age may selectively diminish spinal pathways involved in the neural control of breathing.
authors.affiliation: Department of Comparative Biosciences, University of Wisconsin, Madison 53706, USA.
authors.forename: L
authors.initials: L
authors.lastname: Ling
authors.forename: K B
authors.initials: KB
authors.lastname: Bach
authors.forename: G S
authors.initials: GS
authors.lastname: Mitchell
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology / Q000502:physiology; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013997:Time Factors
chemical_list: D006916:5-Hydroxytryptophan