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Segmental Distribution Of Common Synaptic Inputs To Spinal Motoneurons During Fictive Swimming In The Lamprey, James T. Buchanan, Stefan Kasicki
Segmental Distribution Of Common Synaptic Inputs To Spinal Motoneurons During Fictive Swimming In The Lamprey, James T. Buchanan, Stefan Kasicki
Biological Sciences Faculty Research and Publications
These experiments were designed to measure the degree of shared synaptic inputs coming to pairs of myotomal motoneurons during swimming activity in the isolated spinal cord of the lamprey. In addition, the experiments measured the decrease in the degree of shared synaptic inputs with the distance between the motoneurons to assess the segmental distribution of these shared inputs. Intracellular microelectrode recordings of membrane potential were made simultaneously on pairs of myotomal motoneurons during swimming activity induced with an excitatory amino acid. The swim cycle oscillations of motoneuron membrane potentials were removed with a digital notch filter, thus leaving the fast …
Effect Of A 17 Day Spaceflight On Contractile Properties Of Human Soleus Muscle Fibres, Jeffrey J. Widrick, Shannon T. Knuth, Kris M. Norenberg, Janell Romatowski, James L. W. Bain, Danny A. Riley, M. Karhanek, S. W. Trappe, Todd A. Trappe, David Costill, Robert Fitts
Effect Of A 17 Day Spaceflight On Contractile Properties Of Human Soleus Muscle Fibres, Jeffrey J. Widrick, Shannon T. Knuth, Kris M. Norenberg, Janell Romatowski, James L. W. Bain, Danny A. Riley, M. Karhanek, S. W. Trappe, Todd A. Trappe, David Costill, Robert Fitts
Biological Sciences Faculty Research and Publications
1. Soleus biopsies were obtained from four male astronauts 45 days before and within 2 h after a 17 day spaceflight. 2. For all astronauts, single chemically skinned post-flight fibres expressing only type I myosin heavy chain (MHC) developed less average peak Ca¥ activated force (Pï) during fixed-end contractions (0·78 ± 0·02 vs. 0·99 ± 0·03 mN) and shortened at a greater mean velocity during unloaded contractions (Vï) (0·83 ± 0·02 vs. 0·64 ± 0·02 fibre lengths s¢) than preflight type I fibres. 3. The flight-induced decline in absolute Pï was attributed to reductions in fibre diameter and Ï or …
Commissural Interneurons In Rhythm Generation And Intersegmental Coupling In The Lamprey Spinal Cord, James T. Buchanan
Commissural Interneurons In Rhythm Generation And Intersegmental Coupling In The Lamprey Spinal Cord, James T. Buchanan
Biological Sciences Faculty Research and Publications
Commissural interneurons in rhythm generation and intersegmental coupling in the lamprey spinal cord. To test the necessity of spinal commissural interneurons in the generation of the swim rhythm in lamprey, longitudinal midline cuts of the isolated spinal cord preparation were made. Fictive swimming was then induced by bath perfusion with an excitatory amino acid while recording ventral root activity. When the spinal cord preparation was cut completely along the midline into two lateral hemicords, the rhythmic activity of fictive swimming was lost, usually replaced with continuous ventral root spiking. The loss of the fictive swim rhythm was not due to …
Physiological And Morphological Correlates Of Presynaptic Inhibition In Primary Afferents Of The Lamprey Spinal Cord, I. V. Batueva, E. A. Tsvetkov, A. K. Sagatelyan, James T. Buchanan, N. Vesselkin, V. Adanina, E. I. Suderevskaya, J. -P Rio, J. Repérant
Physiological And Morphological Correlates Of Presynaptic Inhibition In Primary Afferents Of The Lamprey Spinal Cord, I. V. Batueva, E. A. Tsvetkov, A. K. Sagatelyan, James T. Buchanan, N. Vesselkin, V. Adanina, E. I. Suderevskaya, J. -P Rio, J. Repérant
Biological Sciences Faculty Research and Publications
Patch-clamp recordings in a whole-cell mode were performed on dorsal sensory cells enzymatically isolated from the spinal cord of two lamprey species, Ichthyomyzon unicuspis and Lampetra fluviatilis. The voltage-activated currents through calcium channels were analysed. GABA and the specific GABAB receptor agonist baclofen reduced the peak amplitude of inward Ba2+ current, as a robust alternate charge carrier through voltage-dependent Ca2+ channels. These effects were dose-dependent and reversible. GABAB receptor antagonists, 2-hydroxysaclofen and δ-amino-n-valeric acid, blocked the reduction of Ba2+ currents by GABA and baclofen, while bicuculline, a GABAA receptor antagonist, had no blocking …
Five Myofibrillar Lesion Types In Eccentrically Challenged, Unloaded Rat Adductor Longus Muscle—A Test Model, Joyce L. Thompson, Edward Michael Balog, Robert H. Fitts, Danny A. Riley
Five Myofibrillar Lesion Types In Eccentrically Challenged, Unloaded Rat Adductor Longus Muscle—A Test Model, Joyce L. Thompson, Edward Michael Balog, Robert H. Fitts, Danny A. Riley
Biological Sciences Faculty Research and Publications
Sarcomere disruptions are observed in the adductor longus (AL) muscles following voluntary reloading of spaceflown and hindlimb suspension unloaded (HSU) rat, which resemble lesions in eccentrically challenged muscle. We devised and tested an eccentric contraction (ECCON) test system for the 14-day HSU rat AL. Six to 7 hours following ECCON, ALs were fixed to allow immunostaining and electron microscopy (EM). Toluidine blue-stained histology semithin sections were screened for lesion density (#/mm2). Serial semithin sections from the ECCON group were characterized for myosin immunointensity of lesions. Five myofibrillar lesion types were identified in histological semithin sections: focal contractions; wide …