Microinjection of neurotensin (NT) into the rostral ventromedial medulla (RVM) produces dose-dependent antinociception. Here we show that antinociception produced by intra-RVM microinjection of neurotensin (NT) or the selective NT receptor subtype 1 (NTR1) agonist PD149163 can be partially blocked by intrathecal (i.t.) yohimbine, an alpha2-adrenoceptor antagonist and by methysergide, a serotonin receptor antagonist. Antinociception produced by the NTR2 agonist beta-lactotensin (beta-LT) is blocked by intrathecal (i.t.) yohimbine, but not by methysergide i.t. It is not known which noradrenergic cell group is involved in this newly identified noradrenergic component of NTR-mediated antinociception. These experiments provide the first evidence that selective activation of NTR2 in the RVM produces antinociception. These results also provide evidence that activation of NTR1 in the RVM produces antinociception through spinal release of norepinephrine (NE) and serotonin, and that activation of NTR2 in the RVM produces antinociception mediated by spinal release of NE.
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http://dx.doi.org/10.1016/j.pain.2007.06.010 | DOI Listing |
bioRxiv
November 2024
Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239, USA.
J Pain
November 2024
Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA; Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA. Electronic address:
Classical preclinical studies show that serotonin (5-HT) injected into the rostral ventromedial medulla (RVM) produces analgesia that is blocked by 5-HT2 receptor antagonists. One key modulator of 5-HT activity is the serotonin transporter (SERT) which reduces serotonergic signaling through reuptake into the presynaptic terminal. In the activity-induced muscle pain model, females show widespread pain and increased SERT expression in the RVM whereas males show localized pain and no changes in SERT expression.
View Article and Find Full Text PDFPain
January 2025
Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.
Pharmacological ablation of rostral ventromedial medulla (RVM) mu opioid receptor-expressing cells before peripheral nerve injury prevents the development of neuropathic pain. However, whether these neurons are required for the expression of established neuropathic pain is not known. Male Oprm1Cre heterozygous (MOR Cre ) or wild-type (MOR WT ) mice received AAV8-hSyn-DIO-hM4D(Gi)-mCherry in the RVM.
View Article and Find Full Text PDFCountries that have a Deposit and Refund System (DRS) show high rates of selective beverage packaging waste collection, indicating that it is a powerful economic instrument for achieving the European packaging recycling targets. DRS ensure that collected material is of a sufficiently high quality to be incorporated into new products. In Portugal, the Government has decided to implement a DRS for non-reusable beverage packaging as a strategy to increase the packaging recycling rate, which is currently considerably lower than the mandatory European targets.
View Article and Find Full Text PDFeNeuro
December 2023
Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201.
Serotonergic neurons in the rostral ventral medulla (RVM) contribute to bidirectional control of pain through modulation of spinal and trigeminal nociceptive networks. Deficits in this pathway are believed to contribute to pathologic pain states, but whether changes in serotonergic mechanisms are pro- or antinociceptive is debated. We used a combination of optogenetics and fiber photometry to examine these mechanisms more closely.
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