Cholinergic terminals in the ventral horn of adult rat and cat: evidence that glutamate is a co-transmitter at putative interneuron synapses but not at central synapses of motoneurons

Liu, T.T., Bannatyne, B.A., Jankowska, E. and Maxwell, D.J. (2009) Cholinergic terminals in the ventral horn of adult rat and cat: evidence that glutamate is a co-transmitter at putative interneuron synapses but not at central synapses of motoneurons. Neuroscience, 161(1), pp. 111-122. (doi: 10.1016/j.neuroscience.2009.03.034)

Abstract

Until recently it was generally accepted that the only neurotransmitter to be released at central synapses of somatic motoneurons was acetylcholine. However, studies on young mice (P0-10) have provided pharmacological evidence indicating that glutamate may act as a co-transmitter with acetylcholine at synapses between motoneurons and Renshaw cells. We performed a series of anatomical experiments on axon collaterals obtained from intracellularly labelled motoneurons from an adult cat and labelled by retrograde transport in adult rats to determine if glutamate is co-localised with acetylcholine by these terminals. We could find no evidence for the presence of vesicular glutamate transporters in motoneuron axon terminals of either species. In addition, we were unable to establish any obvious relationship between motoneuron terminals and the GluR2 subunit of the AMPA receptor. However we did observe a population of cholinergic terminals in lamina VII which did not originate from motoneurons but were immunoreactive for the vesicular glutamate transporter 2 and formed appositions to GluR2 subunits. These were smaller than motoneuron terminals and, unlike them, formed no relationship with Renshaw cells. The evidence suggests that glutamate does not act as a co-transmitter with acetylcholine at central synapses of motoneurons in the adult cat and rat. However, glutamate is present in a population of cholinergic terminals which probably originate from interneurons where its action is via an AMPA receptor

• Item Type: Articles
• Keywords: spinal cord, motor control, Renshaw cell, acetylcholine, immunocytochemistry
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Maxwell, Professor David
• Authors: Liu, T.T., Bannatyne, B.A., Jankowska, E., and Maxwell, D.J.
• Subjects: R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Neuroscience
• ISSN: 0306-4522