The influence of brain-derived neurotrophic factor (BDNF) upon the nigrostriatal dopaminergic system was evaluated in weanling and adult mice carrying a targeted inactivated BDNF gene. Regional specificity of this BDNF mutation was assessed by…
Deletion of a single copy of the BDNF gene has been shown to affect the nigrostriatal dopaminergic system of young adult BDNF mice. In the present report we evaluated various indices of nigrostriatal dopaminergic function between
The effects of a deletion for the brain derived neurotrophic factor (BDNF) allele (+/- BDNF) upon age-related changes in nigrostriatal dopaminergic (NSDA) function were assessed. Behavioral (beam crossing and spontaneous activity) and neurochemical…
Multiple isoforms of the contractile protein myosin are present in mammalian skeletal muscles. The diversity of the heavy-chain subunits of myosin (MyHCs) in intrafusal fibers is thought to reflect a pathway of differentiation that is unique to…
Whether two copies of the neurotrophin-3 (NT3) gene are necessary for proper development of cardiac sympathetic innervation was investigated in mice carrying a targeted inactivation of the NT3 gene. Heterozygous (+/-) and null (-/-) mutant mice had…
Features of the nerve supply and the encapsulated fibers of muscle spindles were assessed in grafted and normal extensor digitorum longus (EDL) muscles of rats by analysis of serial 10-microns frozen transverse sections stained for enzymes which…
Expression of myosin heavy chain (MHC) isoforms was studied in rat soleus (SOL) and extensor digitorum longus (EDL) muscles which regenerated in the presence or absence of innervation. Frozen sections of two 5 day denervated SOL and EDL grafts, two…
The nuclear bag1 intrafusal fiber mediates the dynamic (velocity) sensitivity, whereas the nuclear bag2 and nuclear chain fibers mediate the static (length) sensitivity of muscle spindles to stretch. The pattern of branching of primary and secondary…
Fusimotor neurons, group Ia afferents and muscle spindles are absent in mutant mice lacking the gene for neurotrophin-3 (NT3). To partition the effect of Ia afferent or spindle absence from that of NT3 deprivation on fusimotor neuron development, we…
Expression of myosin heavy chain (MHC) isoforms was studied in rat soleus (SOL) and extensor digitorum longus (EDL) muscles which regenerated in the presence or absence of innervation. Frozen sections of two 5 day denervated SOL and EDL grafts, two…
The incidence of coated vesicles under sarcolemmal surfaces of equatorial, juxtaequatorial and polar regions in developing and adult spindles of the rat soleus muscle was examined by quantitative morphometry of transverse ultrathin sections. Coated…
Depletion of dopamine (DA) reduces D, receptor number, but D-3 receptor expression is also regulated by brain-derived neurotrophic factor (BDNF). We took advantage of transgenic heterozygous BDNF mutant mice (+/-) to determine if reduced BDNF and…
ER81, a member of the ETS family of transcription factors, is essential for the formation of connections between sensory and motor neurons in the spinal cord. Mice lacking Er81 genes exhibit reduced monosynaptic sensory-motoneuron connectivity in…
The effects of a deficiency of neurotrophin-3 on spinal motor neurons were assessed by determining the number of myelinated nerve fibers in lumbar ventral spinal roots of mice with a deletion in the neurotrophin-3 gene. Few or no small-caliber…
NEUROTROPHIN-3 (NT3) or TrkC null mutant mice were examined for the presence of muscle spindles. Muscles of mastication, but not limbs, contained spindles in newborn and adolescent mutants. The intramuscular distribution and morphological properties…
Crushing the nerve to the medial gastrocnemius (MG) muscle at birth and administering nerve growth factor to rats afterwards results in a reinnervated muscle with supernumerary muscle spindles, some of which must have formed de novo. Structure and…
The pattern of regional expression of a slowtonic myosin heavy chain (MHC) isoform was studied in developing rat soleus intrafusal muscle fibers. Binding of the slow-tonic antibody (ATO) began at the equator of prenatal intrafusal fibers where…
Whether muscle spindles can form in muscles innervated only by afferents was investigated by removing the lumbosacral segment of the spinal cord immediately after crushing the nerve to the medial gastrocnemius (MG) muscle in newborn rats, and…
Muscle fibers develop sequentially from several generations of myotubes that express specific isoforms of myosin heavy chain (MHC). We observed that the chicken-derived monoclonal antibody (mAb) S46 binds to myotubes of the fetal rat hindlimb in a…
S46, a monoclonal antibody (mAb) specific for the SM-1 and SM-2 isoforms of avian slow myosin heavy chains (MHC), was used to study the earliest stages of development of intrafusal fibers in muscle spindles of the rat hindlimb. Spindles formed only…
A rat muscle spindle typically contains four intrafusal fibers - one nuclear bag(2), one nuclear bag, and two nuclear chain fibers. We compared the sequence of formation of the three intrafusal fiber types among the tibialis anterior (TA), soleus…
