Péter Szucs

Publications of Péter Szucs

• Neurotransmitter systems of commissural interneurons in the lumbar spinal cord of neonatal rats.

  Authors: Ildikó Wéber, Gábor Veress, Péter Szucs, Miklós Antal, András Birinyi

  Brain research. 11/2007; 1178:65-72.

  The circuits that generate rhythmic locomotor activities are located in the ventromedial area of the lumbar spinal cord and comprise commissural interneurons necessary for left-right alternationThe circuits that generate rhythmic locomotor activities are located in the ventromedial area of the lumbar spinal cord and comprise commissural interneurons necessary for left-right alternation during walking movements. In this study we injected biotinylated dextran amine (BDA) into the ventromedial gray matter of the lumbar spinal cord of neonatal rats to label commissural interneurons. Anterogradely labeled axons arose from the site of injection, crossed the midline in the anterior commissure and arborized extensively in the contralateral ventral horn of the spinal cord. The presence of neurotransmitter systems in labeled axon terminals of commissural interneurons was investigated by using antibodies raised against specific transmitter-related proteins. Boutons potentially containing inhibitory amino acids were identified by applying glutamic acid decarboxylase (GAD65/67) and glycine transporter 2 antibodies. Out of 1146 BDA-labeled axon terminals, 663 boutons were assumed on this basis to be inhibitory; 76% of these terminals were immunoreactive for glycine transporter, 53% were immunoreactive for GAD and about 30% of inhibitory boutons might contain both inhibitory amino acids. Boutons potentially containing putative excitatory neurotransmitter were revealed with antibodies raised against vesicular glutamate transporters 1 and 2. Out of 590 BDA-labeled boutons about one fourth (158) were immunoreactive for glutamate transporters. These mammalian commissural interneurons are compared to the glycinergic commissural interneurons in the swimming CPGs of lamprey and the Xenopus tadpole. Our results show that commissural interneurons in the mammalian spinal cord form a heterogeneous group including glutamatergic excitatory and GABAergic and glycinergic inhibitory neurons.

• Hyperpolarization-activated and cyclic nucleotide-gated cation channel subunit 2 ion channels modulate synaptic transmission from nociceptive primary afferents containing substance P to secondary sensory neurons in laminae I-IIo of the rodent spinal dorsal horn.

  Authors: Ildikó Papp, Péter Szucs, Krisztina Holló, Ferenc Erdélyi, Gábor Szabó, Miklós Antal

  The European journal of neuroscience. 10/2006; 24(5):1341-52.

  We have previously demonstrated that hyperpolarization-activated and cyclic nucleotide-gated cation channel subunit 2 (HCN2) is expressed by terminals of peptidergic nociceptive primary afferents inWe have previously demonstrated that hyperpolarization-activated and cyclic nucleotide-gated cation channel subunit 2 (HCN2) is expressed by terminals of peptidergic nociceptive primary afferents in laminae I-IIo of the rat spinal dorsal horn. In this study, we investigated the possible neurotransmitters and postsynaptic targets of these HCN2-expressing primary afferent terminals in the superficial spinal dorsal horn by using immunocytochemical methods. We demonstrated that HCN2 widely colocalizes with substance P (SP), and that HCN2-positive terminals that are also immunoreactive for SP form serial close appositions with dendrites and perikarya of neurokinin 1 receptor-immunoreactive neurons. It was also found that HCN2-immunoreactive terminals are frequently apposed to neurons that are immunoreactive for calbindin, micro-opioid receptor and the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor subunit GluR2, markers for excitatory interneurons. Investigating HCN2 immunoreactivity in glutamic acid decarboxylase 65-green fluorescent protein transgenic mice, we found that HCN2-positive terminals occasionally also contact cells that contain an isoform of glutamic acid decarboxylase (glutamic acid decarboxylase 65), a marker for GABAergic inhibitory neurons. Application of ZD7288, an antagonist of HCN channels, onto neurons that were recorded in spinal cord slices with whole-cell patch-clamp electrodes reduced the number of monosynaptic excitatory postsynaptic potentials evoked by electrical stimulation of primary afferents at nociceptive intensities. The results suggest that HCN2 may contribute to the modulation of membrane excitability of SP-containing nociceptive primary afferent terminals, may increase the reliability of synaptic transmission from primary afferents to secondary sensory neurons and thus may play a role in the fine-tuning of pain transmission from nociceptive primary afferents to neurons in the spinal dorsal horn.