Neuropeptides
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The neuropeptide galanin (GAL) is involved in the control of hormone secretion, nociception, feeding behavior, attention, learning and memory. The anatomical localization of galanin receptors in the brain has been described using autoradiography and immunohistochemistry, but both techniques are limited by the availability of specific radioligands or antibodies. Functional autoradiography provides an alternative method by combining anatomical resolution and information of the activity mediated by G-protein coupled receptors. ⋯ The activity mediated by GAL receptors in human and rat brain showed a good correlation of the net stimulation in areas such as spinal cord, periaqueductal gray, putamen, CA3 layers of hippocampus, substantia nigra and diverse thalamic nuclei. The functional GAL receptors coupled to Gi/o-proteins showed a similar pattern for both species in most of the areas analyzed, but some discrete nuclei showed differences in the activity mediated by GAL, such as the ventroposteromedial thalamic nucleus, or areas that regulate learning and memory processes in the hippocampus. Taken into consideration the present results, the rat could be used as an experimental model for the study of the physiological role of GAL-mediated neurotransmission and the modulation of GAL receptors activity in the human CNS.
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Paclitaxel in chemotherapy-induced peripheral neuropathy (CIPN) is predominantly with a dose-limiting effect on neuropathic pain in clinical strategy. In the present study, the relationship between the neuropathic pain and nerve degeneration in paclitaxel CIPN was investigated. Adult male Sprague-Dawley (SD) rats were divided into three paclitaxel groups (0.5, 1.0, 2.0mg/kg) and a vehicle group with four intraperitoneal (i.p.) injections on alternating days. ⋯ On the contrary, the density for peptidergic calcitonin gene-related peptide (CGRP)-IR IENFs in paclitaxel groups were revealed the similar decreasing levels (82.75±0.91%, 84.34±3.20%, 81.99±0.25%, respectively; vs. vehicle group, p<0.05). Linear regression analyses exhibited that densities of IENFs for PGP 9.5, SP, CGRP were correlated with withdrawal latencies (r(2)=0.77, p<0.0001; r(2)=0.75, p<0.0001; r(2)=0.28, p=0.0001, respectively) and mechanical thresholds (r(2)=0.43, p<0.0001; r(2)=0.73, p<0.0001; r(2)=0.40, p<0.0001, respectively). Therefore, the present results suggested that the development of neuropathic pain following paclitaxel injection induced the progressive degeneration of IENFs in skin and gave the evidence that the peptidergic IENFs may play an important role in therapeutic strategy of paclitaxe CIPN.
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Cocaine-and-Amphetamine Regulated Transcript peptide (CART peptide) is known for having an inhibitory effect on dopamine (DA)- and cocaine-mediated actions and is postulated to be a homeostatic, regulatory factor in the nucleus accumbens (NAc). Some sex differences in cocaine-mediated locomotor activity (LMA) and in the expression and function of CART peptide have been reported. ⋯ The results show that CART 55-102 blunted or reduced both the DA- and cocaine-induced LMA in both males and females. In conclusion, CART peptide is effective in blunting DA- and cocaine-mediated LMA in both males and females.
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Clinicopathological studies on patients succumbing to subarachnoid haemorrhage (SAH) demonstrated hypothalamic lesions. The implication of the hypothalamic neuropeptides arginine-vasopressin (AVP) and oxytocin (OXT) has not been linked to aneurysmal SAH yet. This study investigates AVP and OXT in CSF and plasma of patients with spontaneous aneurysmal SAH and their association with outcome. ⋯ Patients with poor outcome after aneurysmal SAH have lower AVP and OXT levels in CSF than patients with good outcome while neuropeptide levels in plasma failed to reflect differences in outcome. The data indicate hypothalamic damage as an aetiologic factor for outcome after aneurysmal SAH.
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To investigate if PACAP and VIP have an effect on CGRP release or NOS activity in the trigeminal ganglion and trigeminal nucleus caudalis and if there can be a difference in effect between PACAP and VIP on these two systems. Furthermore, we investigate if PACAP co-localize with CGRP and/or nNOS in the two tissues. ⋯ PACAP-38 cause release of CGRP from TNC but not from TG. We suggest that the release is not caused via activation of PAC1, VPAC1 or VPAC2 receptors. PACAP has no effect on NOS activity in TG or TNC. In TG PACAP was found in neuronal cells and in satellite glial cells. It co-localized with CGRP and nNOS in the neuronal cells. In TNC PACAP was co-localized with CGRP but not with nNOS.