Cellular neurosciencePostnatal appearance of 5-HT2A receptors on fast flexor and slow extensor rat motor neurons
Section snippets
Subjects
One day to 2 week old male and female Wistar rats and adult male Wistar rats weighing ∼300g (B&K Universal, Sollentuna, Sweden) were used. Care was taken to minimize suffering of the animals and to keep the number of experimental animals as low as possible. The experiments were approved by the Norwegian Animal Research Authority in accordance with Norway’s Animal Protection Act and overseen by the veterinarian responsible for the animal house at the department. The Norwegian legislation
5-HT2A receptors appear on SOL and EDL motor neurons between postnatal days 7 and 14
Injection of TMR-dextran into EDL and SOL muscles on postnatal days 1–3 resulted in retrograde labeling of EDL and SOL motor neurons, the column of SOL motor neurons being located more caudally than the EDL column (Fig. 1). On postnatal day 7, neither SOL motor neurons (Fig. 2B) nor EDL motor neurons (not shown) displayed immunoreactivity for 5-HT2A receptors. But cell structures around the central canal were labeled (Fig. 2B inset). On postnatal day 14, the antibody labeled both SOL and EDL
Discussion
Three findings stand out from this work. First, SOL and EDL motor neurons begin to display detectable 5-HT2A receptors between postnatal days 7 and 14. Second, many more SOL than EDL motor neurons display such receptors. Third, on SOL motor neurons, the receptors appear more often on cell body and dendrites than on dendrites only, whereas on EDL motor neurons, they appear more often on dendrites only.
References (44)
Development of serotonin immunoreactivity in the rat spinal cord and its plasticity after neonatal spinal cord lesions
Brain Res
(1987)- et al.
Neurotrophins and trk-receptors in adult rat spinal motoneuronsdifferences related to cell size but not to “slow/fast” specialization
Neurosci Lett
(2000) - et al.
Development of neuromuscular junctions in rat embryos
Dev Biol
(1981) - et al.
Serotonin and L-norepinephrine as mediators of altered excitability in neonatal rat motoneurons studied in vitro
Neuroscience
(1992) - et al.
Functional role of plateau potentials in vertebrate motor neurons
Curr Opin Neurobiol
(1998) Adaptive transformation of rat soleus motor units during growth
J Neurol Sci
(1976)- et al.
The cellular localization of 5-HT2A receptors in the spinal cord and spinal ganglia of the adult rat
Brain Res
(1998) - et al.
Changes in activity patterns in slow and fast muscles during postnatal development
Dev Brain Res
(1983) - et al.
Safety factor at the neuromuscular junction
Prog Neurobiol
(2001) - et al.
Distribution of 5-hydroxytryptamine-immunoreactive boutons on alpha-motoneurons in the lumbar spinal cord of adult cats
J Comp Neurol
(1998)
Expression of myosin heavy chain isoforms in stimulated fast and slow rat muscles
J Neurosci
Synaptic activation of plateaus in hindlimb motoneurons of decerebrate cats
J Neurophysiol
Perinatal switch from synchronous to asynchronous activity of motoneuronslink with synapse elimination
Proc Natl Acad Sci U S A
Dendritic L-type calcium currents in mouse spinal motoneuronsimplications for bistability
Eur J Neurosci
Properties of motor units in fast and slow skeletal muscles of the rat
J Physiol
The 5-HT2A receptor is widely distributed in the rat spinal cord and mainly localized at the plasma membrane of postsynaptic neurons
J Comp Neurol
Electrical stimulation resembling normal motor-unit activityeffects on denervated fast and slow rat muscles
J Physiol
Bistable firing properties of soleus motor units in unrestrained rats
Acta Physiol Scand
Coupling between serotoninergic and noradrenergic neurones and gamma-motoneurones in the cat
J Physiol
Fibre types, calcium-sequestering proteins and metabolic enzymes in denervated and chronically stimulated muscles of the rat
J Physiol
Firing patterns of motor units in normal rats
Nature
Effects of chronic stimulation on the size and speed of long-term denervated and innervated rat fast and slow muscles
Acta Physiol Scand
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Present address: Department of Orthopaedics, Lund University Hospital, Lund, Sweden.