Neuroscience center

Research activities:

The nonapeptide vasopressin acts both as a hormone and as a neurotransmitter/neuromodulator. As a hormone, its target organs include kidney, blood vessels, liver, platelets and anterior pituitary. As a neurotransmitter/neuromodulator, vasopressin plays a role in autonomic functions, such as cardiovascular and temperature regulation, and is involved in complex behavioral and cognitive functions, such as sexual behavior, pair-bond formation and social recognition. Vasopressin exerts its effects by stimulating receptors of the G protein-coupled family. At the neuronal level, vasopressin enhances membrane excitability and modulates synaptic transmission. In particular, vasopressin exerts a powerful excitatory action on brainstem and spinal motoneurons. This effect is due to the generation of a sustained cationic inward current that is TTX-insensitive, sodium- and voltage-dependent and is modified by extracellular calcium. A major unsolved problem is: what's the second messenger responsible for the neuronal action of vasopressin? The main objective of our research program is to characterize the intracellular signaling pathway linking vasopressin receptors to the nonspecific cation channels whose opening is responsible for the peptide-induced excitation in motoneurons. These studies should help elucidate the role played by central vasopressin in the control of motor activity.

Selected Publications:

• Raggenbass, M., Overview of cellular electrophysiological actions of vasopressin. Eur J Pharmacol, 2008. 583(2-3): p. 243-254.
• Allaman-Exertier, G., I. Reymond-Marron, E. Tribollet, and M. Raggenbass, Vasopressin modulates lateral septal network activity via two distinct electrophysiological mechanisms. Eur J Neurosci, 2007. 26(9): p. 2633-2642.
• Ogier, R., E. Tribollet, P. Suarez, and M. Raggenbass, Identified motoneurons involved in sexual and eliminative functions in the rat are powerfully excited by vasopressin and tachykinins. J Neurosci, 2006. 26(42): p. 10717-10726.
• Reymond-Marron, I., E. Tribollet, and M. Raggenbass, The vasopressin-induced excitation of hypoglossal and facial motoneurons in young rats is mediated by V1a but not V1b receptors, and is independent of intracellular calcium signalling. Eur J Neurosci, 2006. 24(6): p. 1565-1574.

Contact:
University Medical Center
Département des neurosciences fondamentales
Email: Mario (dot) Raggenbass (at) unige (dot) ch