Noradrenergic Modulation of Intrinsic and Synaptic Properties of Lumbar Motoneurons in the Neonatal Rat Spinal Cord

نویسندگان

  • Maylis Tartas
  • France Morin
  • Grégory Barrière
  • Michel Goillandeau
  • Jean-Claude Lacaille
  • Jean-René Cazalets
  • Sandrine S. Bertrand
چکیده

Although it is known that noradrenaline (NA) powerfully controls spinal motor networks, few data are available regarding the noradrenergic (NAergic) modulation of intrinsic and synaptic properties of neurons in motor networks. Our work explores the cellular basis of NAergic modulation in the rat motor spinal cord. We first show that lumbar motoneurons express the three classes of adrenergic receptors at birth. Using patch-clamp recordings in the newborn rat spinal cord preparation, we characterized the effects of NA and of specific agonists of the three classes of adrenoreceptors on motoneuron membrane properties. NA increases the motoneuron excitability partly via the inhibition of a K(IR) like current. Methoxamine (alpha(1)), clonidine (alpha(2)) and isoproterenol (beta) differentially modulate the motoneuron membrane potential but also increase motoneuron excitability, these effects being respectively inhibited by the antagonists prazosin (alpha(1)), yohimbine (alpha(2)) and propranolol (beta). We show that the glutamatergic synaptic drive arising from the T13-L2 network is enhanced in motoneurons by NA, methoxamine and isoproterenol. On the other hand, NA, isoproterenol and clonidine inhibit both the frequency and amplitude of miniature glutamatergic EPSCs while methoxamine increases their frequency. The T13-L2 synaptic drive is thereby differentially modulated from the other glutamatergic synapses converging onto motoneurons and enhanced by presynaptic alpha(1) and beta receptor activation. Our data thus show that the NAergic system exerts a powerful and complex neuromodulation of lumbar motor networks in the neonatal rat spinal cord.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Study of the Effects of Horsetail Stem Extract Administration on the Numerical Density of Alpha Motoneurons in the Ventral Horn of Lumbar Spinal Cord of Compressed Sciatic Nerve of Rat

Purpose: The goal of this research was to study of the protective effects horse tail (HT) plant extract on the central degeneration of alpha motoneurons (AM) of spinal cord.Materials and Methods: The lesioned sciatic rats were divided into sham, control and 3 experimental groups and treated by 15 mg/kg, ip HT extract. The animals were care for one month and then were sacrificed and perfused car...

متن کامل

The effect of acetyl l-carnitine on ultrastructure of injured motoneuron synapses in adult rat

Background and Objective: Spinal cord compression is a relatively common neurological complication in developing country. This study was designed to assess neuroprotective effect of acetyl L-carnitine. Materials and Methods: 16 adult Sprague Dawley rats weighing 250 to 300 g were divided into 4 randomized groups, namely, A-laminectomy with daily intraperitoneal injection of acetyl L-carnitine....

متن کامل

Time Course of Axotomy-induced Changes in Synaptophysin Pattern and Synaptic Reaction of Spinal Motoneurons in Adult Rat

Background and Objective: Evaluation of degenerative changes of motoneurons and their related synapses can be useful in understanding the mechanisms of neurodegenerative diseases and their potential treatment. The present electron microscopic and immunohistochemical study investigates the axotomy-induced...

متن کامل

Rapid activity-dependent modulation of the intrinsic excitability through up-regulation of KCNQ/Kv7 channel function in neonatal spinal motoneurons

Activity-dependent changes in the properties of the motor system underlie the necessary adjustments in its responsiveness on the basis of the environmental and developmental demands of the organism. Although plastic changes in the properties of the spinal cord have historically been neglected because of the archaic belief that the spinal cord is constituted by a hardwired network that simply re...

متن کامل

Deprenyl increases synaptophysin and choline acetyltransferase in rat after sciatic nerve axotomy

Neuroprotective effect of deprenyl on motoneurons of spinal cord after axotomy of peripheral nerves such as sciatic has been well established. Deprenyl is an inhibitor of monoamine oxidase type-B (MAO-B). The main function of this agent is the release of neurotransmitters from pre-synaptic terminals. Acetylcholine is a neurotransmitter that is synthesized by choline acetyltransferase (ChAT) and...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 4  شماره 

صفحات  -

تاریخ انتشار 2010