Abstract Wallerian degeneration of the distal stump a severed peripheral nerve involves invasion by myelomonocytic cells, whose presence is necessary for destruction myelin and initiating mitosis in Schwann cells (Beuche Friede, 1984). Degeneration ends axons themselves assumed to occur autolytic mechanisms. We describe strain mice (C57BL/6/Ola) which leucocyte slow sparse. In these mice, confirming Beuche removal extremely slow. A new finding that axon also very This consequence lack...

Using mAbs and immunocytochemistry we have examined the response of macrophages (M phi) after crush injury to sciatic or optic nerve in mouse rat. We established that large numbers M phi enter peripheral nerves containing degenerating axons; are localized portion damaged axons, they phagocytose myelin. The period recruitment is before during maximal proliferation Schwann cells. In contrast, attracts few phi, removal myelin much slower. These results show clearly different responses damage...

1. Longitudinal vibration was applied to the de‐efferented soleus muscle of anaesthetized cats while recording discharge single afferent fibres from proprioceptors within muscle. Conditions were defined under which can be used excite selectively primary endings spindles without exciting secondary or Golgi tendon organs. 2. Frequencies 100‐500 c/s used. The maximum amplitude vibrator could produce fell with increasing frequency; it 250 μ (peak peak) for 100 and 20 500 c/s. 3. Primary very...

The efferent crossed olivocochlear bundle (c.o.c.b.) was electrically stimulated during intracellular recordings from cochlear inner hair cells in anaesthetized guinea‐pigs. effect of c.o.c.b. stimulation to decrease the magnitude cell depolarizing component (d.c.) and alternating (a.c.) receptor potentials evoked by tone bursts at characteristic frequency. At low sound pressure levels, caused equivalent decreasing intensity 9‐24 dB. C.o.c.b. usually had a similar on compound action...

Horseradish peroxidase was used to label axons of olivocochlear (OC) neurons by intracellular injections in cats and extracellular rodents. These arise from cell bodies the superior olivary complex project cochlea. En route cochlea, thick (greater than 0.7 micron diam.) medial (MOC) formed collaterals that terminated ventral cochlear nucleus, interstitial nucleus vestibular nerve (in cats), inferior rodents). The thin (less diam.), presumed lateral (LOC) neurons, did not branch near CN....

1. The experiments were performed on the soleus muscle of anaesthetized cat in which ventral roots had been cut. 2. A short period repetitive stimulation a single fusimotor fibre influenced particular spindle primary ending invariably caused characteristic alteration response same to subsequently applied ramp stretch muscle. change consisted appearance burst impulses at beginning where none present before. Occasionally, such an ‘initial burst’ was spontaneously present; it then enhanced...

Abstract Previous attempts to trace the central pathways of thin axons from type II spiral ganglion neurons have been hampered by technical difficulties such as fading reaction product distance increases injection site (Ryugo et al.: Soc. Neurosci. Abstr. 12: 779, '86; Brown: J. Comp. Neurol. 260: 591–604, '87). By using small rodents (gerbils and mice), which short auditory nerves, we succeeded in filling entire axon terminals after peripheral injections horseradish peroxidase. The general...

The cholinergic efferent fibers to the outer hair cells (OHCs) of mammalian cochlea suppress sound-evoked activity auditory nerve on two time scales via one nicotinic receptor. A rapid action (tens milliseconds) is responsible for modulating responses acoustic stimulation. slower seconds) may protect ear from overstimulation. likely caused by calcium influx through receptor that leads opening calcium-activated potassium (KCa) channels, but mechanism has not been explained. To investigate...

Norrie disease is an X-linked recessive syndrome of blindness, deafness, and mental retardation. A knock-out mouse model with an<i>Ndp</i> gene disruption was studied. We examined the hearing phenotype, including audiological, histological, vascular evaluations. As seen in humans, mice had progressive loss leading to profound deafness. The primary lesion localized stria vascularis, which houses main vasculature cochlea. Fluorescent dyes showed abnormal this region eventual two-thirds...

Abstract Efferent axons to the guinea pig cochlea were labeled by extracellular injections of horseradish peroxidase into intraganglionic spiral bundle within ganglion. The terminal fibers formed these classified according their patterns termination basal turn cochlea. A class designated “autonomic” forms a highly branched plexus in osseous lamina but does not enter organ Corti. single autonomics includes blood vessels as well areas adjacent vessels. Two major classes efferent from...

The retinoblastoma protein pRb is required for cell-cycle exit of embryonic mammalian hair cells but not their early differentiation. However, its role in postnatal unknown. To study the function mature animals, we created a new conditional mouse model, with Rb gene deleted primarily inner ear. Progeny survive up to 6 months. During development, −/− continue divide and can transduce mechanical stimuli. adult mice exhibit profound hearing loss due progressive degeneration organ Corti. We show...

Abstract Cochlear afferent and efferent fibers in the guinea pig were labeled by focal extracellular injections of horseradish peroxidase into spiral ganglion basal turn. The morphology pattern termination these studied light microscopy. Fibers peripheral side could be grouped on basis their courses terminations cochlea two classes fibers, (olivocochlear) other presumably autonomic fibers. This paper describes characteristics parent cells. Peripheral major classes: (1) thick (mean diameter...

In a substrain of C57BL mice, C57BL/Ola, Wallerian degeneration in the distal segment severed sciatic nerve is extremely slow when compared to other mice. Despite this very regeneration motor nerves not impaired. From suitable genetic outcrosses and backcrosses, authors provide evidence that rate strain controlled by single autosomal gene product. The have also shown degeneration, C57BL/Ola influenced environment which animals were bred housed. mice raised isolators slower than those...

Intracellular recordings were obtained from inner hair cells located in the lower basal turn of guinea pig cochlea. At low sound pressure levels highly frequency selective, producing receptor potentials only response to frequencies between about 16 and 24 kilohertz. Electrical stimulation efferent nerves crossed olivocochlear bundle markedly reduced these while causing little change resting membrane potential. high levels, where responded an increasingly wider range frequencies, was less...

Cochlear nucleus branches of thick olivocochlear axons were labeled by injections horseradish peroxidase into the spiral ganglion cochlear basal turn in mice. Six traced light microscopy, and selected portions seven sectioned serially for electron microscopic examination. Axonal most frequently terminated near certain granule cell regions ventral nucleus. This article describes terminals, synapses, postsynaptic elements these branches. The had both terminal en passant boutons that contained...