Search results for "Relaxin-3"
showing 5 items of 5 documents
Electrolytic lesion of the nucleus incertus retards extinction of auditory conditioned fear
2013
Fear memory circuits in the brain function to allow animals and humans to recognize putative sources of danger and adopt an appropriate behavioral response; and research on animal models of fear have helped reveal the anatomical and neurochemical nature of these circuits. The nucleus (n.) incertus in the dorsal pontine tegmentum provides a strong GABAergic projection to forebrain ‘fear centers’ and is strongly activated by neurogenic stressors. In this study in adult male rats, we examined the effect of electrolytic lesions of n. incertus on different stages of the fear conditioning-extinction process and correlated the outcomes with anatomical data on the distribution of n. incertus-derive…
Modulation of hippocampal theta oscillations and spatial memory by relaxin-3 neurons of the nucleus incertus.
2009
Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that “pacemaker” neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the neuropeptide relaxin-3 (RLN3). Therefore, this study examined the possible contribution of RLN3 to MS activity, and associated hippocampal theta activity and spatial memory. In anesthetized and conscious rats, we identified the ability of intraseptal RLN3 signaling to modulate neuronal activity in the MS and hippocampus and promote hippocampal the…
Distribution and targets of the relaxin-3 innervation of the septal area in the rat.
2012
Neural tracing studies have revealed that the rat medial and lateral septum are targeted by ascending projections from the nucleus incertus, a population of tegmental GABA neurons. These neurons express the relaxin-family peptide, relaxin-3, and pharmacological modulation of relaxin-3 receptors in medial septum alters hippocampal theta rhythm and spatial memory. In an effort to better understand the basis of these interactions, we have characterized the distribution of relaxin-3 fibers/terminals in relation to different septal neuron populations identified using established protein markers. Dense relaxin-3 fiber plexuses were observed in regions of medial septum containing hippocampal-proje…
Nucleus incertus—An emerging modulatory role in arousal, stress and memory
2011
A major challenge in systems neuroscience is to determine the underlying neural circuitry and associated neurotransmitters and receptors involved in psychiatric disorders, such as anxiety and depression. A focus of many of these studies has been specific brainstem nuclei that modulate levels of arousal via their ascending monoaminergic projections (e.g. the serotonergic dorsal raphe, noradrenergic locus ceruleus and cholinergic laterodorsal tegmental nucleus). After years of relative neglect, the subject of recent studies in this context has been the GABAergic nucleus incertus,1 which is located in the midline periventricular central gray in the ‘prepontine’ hindbrain, with broad projection…
Glutamatergic projection from the nucleus incertus to the septohippocampal system
2012
Abstract Recent findings support a relevant role of the nucleus incertus in the control of the hippocampal activity through the modulation of theta rhythm. Previous studies from our group have shown that this nucleus is a critical relay between reticularis pontis oralis and the medial septum/diagonal band, regarded as the main activator and the pacemaker of the hippocampal oscillations, respectively. Besides, the nucleus incertus is highly linked to activated states related to the arousal response. The neurotransmission of the nucleus incertus, however, remains uncertain. Only GABA and the neuromodulator relaxin 3 are usually considered to be involved in its contribution to the septohippoca…