Effects of serotonin antagonists on motion sickness and its suppression by 8-OH-DPAT in cats.
This investigation evaluated the antagonist properties of (-)propranolol, (+)propranolol, metergoline and BMY 7378 on the known effect of 8-OH-DPAT (DPAT) to decrease motion sickness in cats. (-)Propranolol produced a greater decrease in the antiemetic effect of DPAT than did (+)propranolol. Although metergoline produced a decrease in the antiemetic effect of DPAT, the decrease could not be clearly attributed to interactions with 5-HT1A receptors because metergoline alone slightly enhanced motion sickness. Depletion of 5-HT with PCPA produced a weaker, nonsignificant enhancement of motion sickness, while mesulergine had no effect. As neither nonspecific 5-HT receptor blockade with metergoline nor depletion of 5-HT mimicked the antiemetic effect of DPAT, it was concluded that DPAT acts on postsynaptic 5-HT1A receptors to prevent emesis. BMY 7378 alone decreased the incidence of motion sickness. A dose just below this agonist range did not decrease the effects of DPAT.
Lucot
J B
JB
Wright State University, Department of Pharmacology, Dayton, OH 45435.
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D002415:Cats; D004305:Dose-Response Relationship, Drug; D004873:Ergolines / Q000494:pharmacology; D005260:Female; D008711:Metergoline / Q000494:pharmacology; D009041:Motion Sickness / Q000188:drug therapy*; D010879:Piperazines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology*; D013237:Stereoisomerism; D013764:Tetrahydronaphthalenes / Q000037:antagonists & inhibitors*
D004873:Ergolines; D010879:Piperazines; D012702:Serotonin Antagonists; D013764:Tetrahydronaphthalenes; D008711:Metergoline; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D011433:Propranolol; C053428:BMY 7378; C031649:mesulergine