Depression of spinal motoneurones by noradrenaline, 5-hydroxytryptamine and histamine

Phillis, John W.; Tebécis, A. K.; York, Donald H.

doi:10.1016/0014-2999(68)90037-x

Cited by 156 publications

(25 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hyperpolarizing inhibitory responses to iontophoresed NE have been reported in many CNS areas, including spinal motoneurons (Phillis et al, 1968;Weight and Salmoiraghi, 1967) and spinal cord explants (Pun et al, 1985), although the specificity of the motoneuron response has been questioned (Engberg et al, 1976). We also sometimes observed early hyperpolarizations after LL region stimulation and, in hyperinnervated motoneurons, a lower membrane potential.…”

Section: Discussionmentioning

confidence: 59%

Noradrenergic hyperinnervation of the motor trigeminal nucleus: alterations in membrane properties and responses to synaptic input

Vornov¹,

Sutin²

1986

J. Neurosci.

View full text Add to dashboard Cite

The physiological consequences of the noradrenergic (NE) hyperinnervation of the rat brain stem produced by neonatal administration of 6-hydroxydopamine (6-OHDA) was studied in the motor trigeminal nucleus. Stimulation of the region of the lateral lemniscus, the source of the noradrenergic innervation of the nucleus, facilitated the masseteric reflex for up to 200 msec in both normal and hyperinnervated animals. The peak facilitation was 71% larger in the NE hyperinnervated animals and was reduced by systemically administered alpha- and beta-adrenergic receptor antagonists. Intracellular recordings revealed that the mean resting potential of NE hyperinnervated trigeminal motoneurons was 3 mV more hyperpolarized than that of normal cells. The mean input resistance of NE hyperinnervated motoneurons was reduced from 1.83 +/- 0.15 to 1.22 +/- 0.19 M Omega. NE hyperinnervation increased the amplitude of the monosynaptic EPSP evoked by stimulation of primary afferent cell bodies in the mesencephalic trigeminal nucleus (MesV) by 65%. The mean rise time of the EPSP was increased in NE hyperinnervated motoneurons while the mean half-width was unchanged, suggesting a shift in the distribution of primary afferent terminals away from the motoneuron soma. Stimulation of the lateral lemniscus region produced a predominantly depolarizing PSP with a time course similar to that of the reflex facilitation. The amplitude of the depolarization in NE hyperinnervated motoneurons was not significantly different from that of controls. During this lateral lemniscus region-evoked PSP, stimulation of MesV produced an EPSP of increased amplitude, associated with a decrease or no change in input resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

Section: Discussionmentioning

confidence: 59%

Noradrenergic hyperinnervation of the motor trigeminal nucleus: alterations in membrane properties and responses to synaptic input

Vornov¹,

Sutin²

1986

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…Recent studies of isolated, hemisected, neonatal spinal cords have also shown 5-HT to have potent depolarizing actions on motoneurones (Connell & Wallis, 1987a). Engberg & Ryall (1966) and Phillis et al (1968) had previously obtained an inhibitory action of 5-HT but this was subsequently shown to be a non-specific effect of the amine (Engberg et al, 1976). Engberg et al (1979) also criticised the use of extracellular recording of the antidromically evoked response of motoneurones and showed that in the cat anaesthetized with barbiu turate, iontophoretically applied 5-HT had little effect on intracellularly or extracellularly recorded responses of motoneurones.…”

Section: Discussionmentioning

confidence: 99%

Effects of 5‐hydroxytryptamine agonists and antagonists on the responses of rat spinal motoneurones to raphe obscurus stimulation

Roberts

Davies

Girdlestone

et al. 1988

British J Pharmacology

View full text Add to dashboard Cite

1The excitability of lumbar spinal motoneurones was studied in halothane-anaesthetized rats by recording with microelectrodes the amplitude of the population spike evoked antidromically by stimulation of the cut ventral roots. 2 Electrical stimulation of the nucleus raphe obscurus for 1 min at 20 Hz increased the population spike amplitude and, as shown by intracellular recording, depolarized motoneurones. This response could be mimicked by microinjection of DL-homocysteic acid into raphe obscurus but the response was not present in animals pretreated wtih the 5-hydroxytryptamine (5-HT) neurotoxin 5,7-dihydroxytryptamine (5,7-DHT). 3 Microiontophoretically applied 5-HT had very similar effects on the extracellularly recorded population spike to those caused by stimulation of the raphe obscurus. These responses to 5-HT were larger in 5,7-DHT-pretreated animals. 4 The effects of 5-HT were potently mimicked by iontophoretically applied 5-carboxamidotryptamine but 8-hydroxy-24di-n-propylamino) tetralin (8-OH-DPAT) was without effect.5 Antagonists were applied by microiontophoresis and also by intravenous injection. Ketanserin, the selective 5-HT2 antagonist, did not antagonize the effects of 5-HT. Neither did the 5-HT3-receptor antagonist MDL 72222 or the selective 5-HT1 binding ligand cyanopindolol. 6 The non-selective 5-HT1/5-HT2-receptor antagonist methysergide was an effective antagonist of both the effects of 5-HT and the response to raphe obscurus stimulation. Methysergide did not reduce the excitatory effects of noradrenaline. 7 It is concluded that 5-HT application and stimulation of raphe obscurus increase the excitability of motoneurones by an action on a 5-HT1-like receptor which appears to be different from the 5-HTlA-and the 5-HTlB-binding sites characterized by others.

show abstract

“…investigating the postsynaptic effects of NE on cat spinal motoneurons reported depressed excitability and/or membrane hyperpolarization, associated with a decrease in a mixed cationic current (334,798,983). In contrast, all recent work indicates that the predominant postsynaptic effects of NE are excitatory, suggesting that the initial findings resulted from a methodological artifact (1362).…”

Section: Pre-and Postsynaptic Actions Of Ne On Motoneurons-early Workmentioning

confidence: 99%

Synaptic Control of Motoneuronal Excitability

Rekling

Funk

Bayliss

et al. 2000

Physiological Reviews

537

482

View full text Add to dashboard Cite

Movement, the fundamental component of behavior and the principal extrinsic action of the brain, is produced when skeletal muscles contract and relax in response to patterns of action potentials generated by motoneurons. The processes that determine the firing behavior of motoneurons are therefore important in understanding the transformation of neural activity to motor behavior. Here, we review recent studies on the control of motoneuronal excitability, focusing on synaptic and cellular properties. We first present a background description of motoneurons: their development, anatomical organization, and membrane properties, both passive and active. We then describe the general anatomical organization of synaptic input to motoneurons, followed by a description of the major transmitter systems that affect motoneuronal excitability, including ligands, receptor distribution, pre-and postsynaptic actions, signal transduction, and functional role. Glutamate is the main excitatory, and GABA and glycine are the main inhibitory transmitters acting through ionotropic receptors. These amino acids signal the principal motor commands from peripheral, spinal, and supraspinal structures. Amines, such as serotonin and norepinephrine, and neuropeptides, as well as the glutamate and GABA acting at metabotropic receptors, modulate motoneuronal excitability through pre-and postsynaptic actions. Acting principally via second messenger systems, their actions converge on common effectors, e.g., leak K + current, cationic inward current, hyperpolarization-activated inward current, Ca 2+ channels, or presynaptic release processes. Together, these numerous inputs mediate and modify incoming motor commands, ultimately generating the coordinated firing patterns that underlie muscle contractions during motor behavior.

show abstract

Depression of spinal motoneurones by noradrenaline, 5-hydroxytryptamine and histamine

Cited by 156 publications

References 13 publications

Noradrenergic hyperinnervation of the motor trigeminal nucleus: alterations in membrane properties and responses to synaptic input

Noradrenergic hyperinnervation of the motor trigeminal nucleus: alterations in membrane properties and responses to synaptic input

Effects of 5‐hydroxytryptamine agonists and antagonists on the responses of rat spinal motoneurones to raphe obscurus stimulation

Synaptic Control of Motoneuronal Excitability

Contact Info

Product

Resources

About