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Biological Activities of Peptides in Brain Tissues
Published in Gerard O’Cuinn, Metabolism of Brain Peptides, 2020
These fibers are relatively sparse in the forebrain compared to other peptides. Moderately dense networks of CGRP-positive fibers have been observed in certain thalamic areas, septum, bed nucleus of the stria terminalis, central amygdaloid nucleus and ventral portion of the caudate nucleus, forming synapses with spiny neurons. Several hypothalamic nuclei are innervated by CGRP-positive fibers, such as the median preoptic area, periventricular region, dorsomedial nucleus and median eminence as well as medial forebrain bundle area. In the lower brainstem, the highest concentrations of these fibers are found in the superficial layers of the sensory trigeminal areas, with moderately dense fiber networks in the periaqueductal gray area, medial geniculate body and parabigeminal nucleus, in and around the lateral lemniscus, in the dorsal aspects of the interpeduncular nucleus, in the parabrachial nucleus, superior olive, cochlear nucleus and nucleus tractus solitarii, especially the lateral parasolitary area, and pars of the vestibular nuclei64,65.
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
A nucleus that lies along the midline, between the right and left VENTRAL TEGMENTAL AREA OF TSAI. (Properly, the term VENTRAL TEGMENTAL AREA should include all of the structures at the base of the MIDBRAIN TEGMENTUM, including the interpeduncular nucleus, but common usage does not do this: the term ventral tegmental area is taken to be synonymous with the ventral tegmental area of Tsai.) Little is known about the interpeduncular nucleus. It sits equidistant from the CEREBRAL PEDUNCLES in each HEMISPHERE, behind the MAMMILLARY BODIES and in front of the most anterior parts of the RAPHE NUCLEI. The interpeduncular nucleus receives output from the HABENULA and projects to the dorsal tegmentum, among other places. Its function is unclear. A rather old literature, based on ELECTROLYTIC LESIONS, suggests it might have a role in certain forms of LEARNING. It is a structure in need of reassessment.
Neuropharmacology Of Amphetamines And Related Stimulants
Published in John Caldwell, S. Joseph Mulé, Amphetamines and Related Stimulants: Chemical, Biological, Clinical, and Sociological Aspects, 2019
Understandings generated by studies which have attempted to delineate the pharmacological effects of amphetamine and other stimulants have contributed significantly to our knowledge base of important neurotransmitter systems, especially the catecholamines. The picture generated over the past few years has implicated other neurotransmitter systems (including serotonin [5HT], acetylcholine [ACh], and γ-amino-butyric acid [GABA]) as modulators of the main dopaminergic and norepinephrinergic effects. For the more potent amphetamine-like psychomotor stimulant effects, even norepinephrine is relegated to a modulating role. As mentioned above, alterations in the phenylisopropylamine nucleus can shift the responsivity of the psychomotor stimulant to a greater activity on the alternative modulating systems. The more robust effects of psychomotor stimulant drugs appear to be mediated by the dopamine system with neurons originating in the substantia nigra and terminating in presynaptic dopamine terminals in the corpus striatum, mainly the caudate nucleus.3A feedback pathway to the substantia nigra dopamine neurons is mediated via ACh, GABA, and perhaps substance “P” interneurons, which inhibit neuronal firing.4 In addition, local short-loop presynaptic dopamine autoreceptors have been implicated in inhibition of dopamine synthesis.5 More recently, dopamine autoreceptors on the substantia nigra dendrites have been reported to inhibit neuronal firing, both when activated with direct dopamine agonists, as well as the indirect-acting psychostimulant, amphetamine.4,6 Four other dopamine systems have been described, including the mesolimbic, mesocortical, tubero-infuendibula, and the retinal. For the purpose of this short review, only the mesolimbic and nigrostriatal systems will be examined. Mesolimbic neurons originating adjacent to the interpeduncular nucleus terminate in the accumbens, the olfactory tubercle, and stria terminalis.7 Norepinephrine systems originate at several loci of the brainstem and are distributed more diffusely into the hypothalamic, mesolimbic, and cortical regions. Norepinephrine mechanisms are considered to be involved in both the ascending and descending reticular activating system, as well as in systems mediating reinforcement and food satiety effects.
Genetic and epigenetic studies of opioid abuse disorder – the potential for future diagnostics
Published in Expert Review of Molecular Diagnostics, 2023
Sarah Abdulmalek, Gary Hardiman
The habenular complex is part of the diencephalic conduction system and is composed of two main domains, the lateral and the median habenula (LHb and MHb). Most projections to the MHb originate from the septum, while the MHb exclusively projects to the interpeduncular nucleus (IPN) [30]. On the other hand, the lateral habenula (LHb) is heavily innervated by brain structures of the limbic system and basal ganglia projecting to the medial and lateral subdivisions of the LHb, respectively. In turn, the LHb projects to key structures of the brainstem. These include dopaminergic VTA and SNc, serotonergic raphe nucleus as well as the GABAergic RMTg. The circuitry in the LHb renders this structure a convergent point of funneled information from major brain systems and a strategic node to relay the processed inputs from the cortex to the brainstem [31].
Activation and blockade of serotonin4 receptors in the lateral habenula improve working memory in unilateral 6-hydroxydopamine-lesioned Parkinson’s rats
Published in Neurological Research, 2019
Yuan Guo, Li Zhang, Jin Zhang, Cheng-Xue Du, Shu-Xuan Lv, Tao Wang, Hui-Sheng Wang, Wen Xie, Jian Liu
Growing evidence indicates that 5-HT system is involved in learning and memory processes [22–24]. Autoradiographic studies indicate that 5-HT4 receptors are more abundant in some brain regions, such as hippocampus, amygdala (Amy), interpeduncular nucleus, LHb, substantia nigra, medial hypothalamus and locus coeruleus of rat [25–30], which suggest a role for the 5-HT4 receptors in cognitive and emotional processes. Several studies have found pro-cognitive effects of 5-HT4 receptor agonists both on short-term memory or long-term olfactory memory [31–33]. However, the role of central 5-HT4 receptors on working memory in parkinsonian rats is still unknown. Therefore, the aim of the present study was to observe (i) the effect of unilateral 6-OHDA lesions of substantia nigra pars compacta (SNc) on working memory measured by the T-maze rewarded alternation test and the role of LHb 5-HT4 receptors in the process; (ii) the effect of LHb 5-HT4 receptor on monoamine levels including DA, noradrenaline (NA) and 5-HT in the brain regions related to working memory; (iii) change in the expression of 5-HT4 receptors on glutamatergic neurons in the LHb after lesioning of the SNc.
The pleiotropic of GLP-1/GLP-1R axis in central nervous system diseases
Published in International Journal of Neuroscience, 2023
LongQing Zhang, Wen Zhang, XueBi Tian
Emerging evidences indicate that GLP-1Rs play a critical role in preclinical model of drug use disorders and systemic application of GLP-1R agonists reduce reward and enhancement of drug abuse [21, 166, 173–177]. It was found that GLP-1R gene deficient mice can significantly enhance cocaine induced motor responses and enhance CPP compared with wild-type accompanied with increasing excitability in GABAergic dorsal lateral septum (dLS) neurons, which could be reversed by treating with AAV-GLP-1R-GFP [176]. And another study showed that pretreatment with Ex-4 blocked amphetamine-induced CPP was ineffective in GLP-1R KDNestin (GLP-1R specifically delete from the CNS) mice, which indicated that GLP-1/GLP-1R axis is beneficial to alleviate drugs addiction [173]. Beside this, drugs of abuse is believed to activate the mesolimbic dopamine system, which play a pivotal role in mediate the reinforcing effects of drugs of abuse and the development of drug abuse and drug dependence [21, 174]. A study implied that Ex-4 reduced acute and chronic cocaine self-administration and attenuated cocaine-induced hyperlocomotion, elevation of striatal dopamine levels and c-fos expression in mice [174]. A human study showed that the plasma concentrations of GLP-1 was significantly reduced post an acute intravenous cocaine infusion which were associated with increasing heart rate, enhancing feeling of high and elevating respiratory rate [178]. As we all know, tobacco smoking is the primary cause of cancer, cardiovascular disease as well as chronic obstructive pulmonary disease [179], nicotine is the key rewarding component in tobacco smoke, which promotes the development of tobacco addiction by activating the mesolimbic dopamine system [180], so it’s urgent to find a new target for treatment of nicotine addiction .A few studies have shown that, in CPP paradigm, treatment with EX-4 can prevent nicotine induced locomotor stimulation, NAc dopamine release in the accumbent septum and memory consolidation of nicotine reward as well as block nicotine induced locomotor sensitization in mice [181]. Furthermore, a study reported that GLP-1R deficit mice had more nicotine intake than wild-type mice, and GLP-1 can excite the GLP-1Rs located in the medial habenular-interpeduncular nucleus (MHb-IPN) circuit, which can abolish nicotine reward and decrease nicotine consumption [182]. Overall, the data indicated that GLP-1/GLP-1R axis may have different effects in multiple drugs addiction.