Additive hypothermic effects of the 5-HT1A receptor agonist 8-OH-DPAT and the dopamine D2/3 receptor agonist 7-OH-DPAT in the rat.
The objective of this study was to examine possible interactions between serotonergic and dopaminergic agents lowering core temperature via stimulation of 5-HT1A and dopamine (DA) D2 receptors, respectively. The effects of the 5-HT1A receptor agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin HBr (8-OH-DPAT) and the DA D2/3 receptor agonist 7-OH-DPAT on core temperature was monitored in adult male Wistar rats, approximately 300 g body weight. The temperature probe was connected to a PC-assisted temperature instrument, and an automated printer device was activated when the temperature reading had stabilized (+/-0.1 degrees C) for 10 s. As expected, 7-OH-DPAT [0.5 and 2.0 micromol x kg(-1) subcutaneous (s.c.)] as well as 8-OH-DPAT (0.15-2.4 micromol x kg(-1) s.c.), produced a dose-dependent hypothermia. When combined, there were additive effects of the two compounds, although the effects of 7-OH-DPAT were attenuated by 8-OH-DPAT at the higher doses (0.6-2.4 micromol x kg(-1)), in all probability because of emerging DA D2 receptor blocking properties of the latter compound.
Eltayb
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Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
Lindblom
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Oerther
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Ahlenius
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D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D018491:Dopamine Agonists / Q000494:pharmacology*; D007035:Hypothermia / Q000139:chemically induced* / Q000503:physiopathology; D008297:Male; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000819:agonists*; D050637:Receptors, Dopamine D3; D011985:Receptors, Serotonin / Q000187:drug effects*; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013764:Tetrahydronaphthalenes / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D018491:Dopamine Agonists; C493595:Drd3 protein, rat; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists; D013764:Tetrahydronaphthalenes; D020891:Raclopride; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C031349:7-hydroxy-2-N,N-dipropylaminotetralin