Opioids are among the most effective drugs to treat severe pain. They produce their analgesic actions by specifically activating opioid receptors located along the pain perception pathway where they inhibit the flow of nociceptive information. This inhibition is partly accomplished by activation of hyperpolarizing G protein-coupled inwardly-rectifying potassium (GIRK or Kir3) channels. Kir3 channels control cellular excitability in the central nervous system and in the heart and, because of their ubiquitous distribution, they mediate the effects of a large range of hormones and neurotransmitters which, upon activation of corresponding G protein-coupled receptors (GPCRs) lead to channel opening. Here we analyze GPCR signaling via these effectors in reference to precoupling and collision models. Existing knowledge on signaling bias is discussed in relation to these models as a means of developing strategies to produce novel opioid analgesics with an improved side effects profile.
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http://dx.doi.org/10.3389/fncel.2014.00186 | DOI Listing |
Insects
January 2025
College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
Inwardly rectifying potassium (Kir) channels regulate essential physiological processes in insects and have been identified as potential targets for developing new insecticides. Flonicamid has been reported to inhibit Kir channels, disrupting the functions of salivary glands and renal tubules. However, the precise molecular target of flonicamid remains debated.
View Article and Find Full Text PDFProg Neurobiol
December 2024
Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, United States. Electronic address:
Most neurons are influenced by multiple neuromodulatory inputs that converge on common effectors. Mechanisms that route these signals are key to selective neuromodulation but are poorly understood. G protein-gated inwardly rectifying K (GIRK or Kir3) channels mediate postsynaptic inhibition evoked by G protein-coupled receptors (GPCRs) that signal via inhibitory G proteins.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, Heilongjiang Province, People's Republic of China. Electronic address:
Photothermal therapy (PTT) is an effective cancer treatment that circumvents the resistance caused by chemotherapy drugs. Conventional PTT has a relatively high temperature, which is better able to kill tumor tissues, but it is also more damaging to normal tissues. Mild PTT avoids these high temperatures, but its corresponding killing ability becomes lower and enhances the heat resistance of cancer cells, causing tumor self-protection and reducing the therapeutic effect of PTT.
View Article and Find Full Text PDFHistol Histopathol
September 2024
Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Albacete, Spain.
G protein-gated inwardly rectifying K (GIRK/K3) channels are mainly expressed in excitable cells such as neurons and atrial myocytes, where they can respond to a wide variety of neurotransmitters. Four GIRK subunits have been found in mammals (GIRK1-4) and act as downstream targets for various Gαi/o-linked G protein-coupled receptors (GPCRs). Activation of GIRK channels produces a postsynaptic efflux of potassium from the cell, responsible for hyperpolarization/inhibition of the neuron.
View Article and Find Full Text PDFBr J Pharmacol
January 2025
Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA.
Background And Purpose: GABAergic neurons in mouse ventral tegmental area (VTA) exhibit elevated activity during withdrawal following chronic ethanol exposure. While increased glutamatergic input and decreased GABA receptor sensitivity have been implicated, the impact of inhibitory signaling in VTA GABA neurons has not been fully addressed.
Experimental Approach: We used electrophysiological and ultrastructural approaches to assess the impact of chronic intermittent ethanol vapour exposure in mice on GABAergic transmission in VTA GABA neurons during withdrawal.
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