Evidence that GABA mediates dopaminergic and serotonergic pathways associated with locomotor activity in juvenile chinook salmon (Oncorhynchus tshawytscha).
The authors examined the control of locomotor activity in juvenile salmon (Oncorhynchus tshawytscha) by manipulating 3 neurotransmitter systems--gamma-amino-n-butyric acid (GABA), dopamine, and serotonin--as well as the neuropeptide corticotropin releasing hormone (CRH). Intracerebroventricular (ICV) injections of CRH and the GABAA agonist muscimol stimulated locomotor activity. The effect of muscimol was attenuated by administration of a dopamine receptor antagonist, haloperidol. Conversely, the administration of a dopamine uptake inhibitor (4',4"-difluoro-3-alpha-[diphenylmethoxy] tropane hydrochloride [DUI]) potentiated the effect of muscimol. They found no evidence that CRH-induced hyperactivity is mediated by dopaminergic systems following concurrent injections of haloperidol or DUI with CRH. Administration of muscimol either had no effect or attenuated the locomotor response to concurrent injections of CRH and fluoxetine, whereas the GABAA antagonist bicuculline methiodide potentiated the effect of CRH and fluoxetine.
Clements
Shaun
S
Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803, USA. clemensh@onid.orst.edu
Schreck
Carl B
CB
D000818:Animals; D004298:Dopamine / Q000502:physiology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D011963:Receptors, GABA-A / Q000502:physiology; D012474:Salmon / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018765:Dopamine Uptake Inhibitors; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D004298:Dopamine