These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Anxiolytic-like activity of the non-selective galanin receptor agonist, galnon.
    Author: Rajarao SJ, Platt B, Sukoff SJ, Lin Q, Bender CN, Nieuwenhuijsen BW, Ring RH, Schechter LE, Rosenzweig-Lipson S, Beyer CE.
    Journal: Neuropeptides; 2007 Oct; 41(5):307-20. PubMed ID: 17637475.
    Abstract:
    Galanin's influence on monoaminergic neurotransmission, together with its discrete CNS distribution in corticolimbic brain areas, points to a potential role for this neuropeptide in mediating anxiety- and depression-like responses. To evaluate this hypothesis, the non-selective galanin receptor agonist, galnon, was tested in multiple preclinical models of anxiolytic- and antidepressive-like activity. Acute administration of galnon (0.03-1mg/kg, i.p.) dose-dependently increased punished crossings in the four plate test, with magnitude similar to the effects of the endogenous ligand, galanin (0.1-1.0 microg, i.c.v.). Moreover, the effects of galnon and galanin were blocked by central administration of the non-selective galanin receptor antagonist, M35 (10 microg, i.c.v.). Interestingly, the benzodiazepine receptor antagonist, flumazenil (1mg/kg, i.p.), reversed galnon's effect in the four plate test, implicating GABAergic neurotransmission as a potential mechanism underlying this anxiolytic-like response. In the elevated zero maze, galnon (0.3-3.0mg/kg, i.p.) and galanin (0.03-0.3 microg, i.c.v.) increased the time spent in the open arms, while in the stress-induced hyperthermia model, galnon (0.3-30 mg/kg, i.p.) attenuated stress-induced changes in body temperature. Consistent with these anxiolytic-like effects, in vivo microdialysis showed that acute galnon (3mg/kg, i.p.) treatment preferentially elevated levels of GABA in the rat amygdala, a brain area linked to fear and anxiety behaviors. In contrast to the effects in anxiety models, neither galnon (1-5.6 mg/kg, i.p.) nor galanin (0.3-3.0 microg, i.c.v.) demonstrated antidepressant-like effects in the mouse tail suspension test. Galnon (1-10mg/kg, i.p.) also failed to reduce immobility time in the rat forced swim test. In vitro, galnon and galanin showed affinity for human galanin receptors expressed in Bowes melanoma cells (K(i)=5.5 microM and 0.2 nM, respectively). Galanin displayed high affinity and functional potency for membranes expressing rat GALR1 receptors (K(i)=0.85 nM; EC(50)=0.6 nM), while galnon (10 microM) failed to displace radiolabeled galanin or inhibit cAMP production in the same GALR1 cell line. Galnon (10 microM) showed affinity for NPY1, NK2, M5, and somatostatin receptors but no affinity for galanin receptors expressed in rat hippocampal membranes. Taken together, the present series of studies demonstrate novel effects of galnon in various preclinical models of anxiety and highlight the galaninergic system as a novel therapeutic target for the treatment of anxiety-related disorders. Moreover, these data indicate rodent GALR1 receptors do not mediate galnon's in vivo activity.
    [Abstract] [Full Text] [Related] [New Search]