There is abundant-evidence implicating the role of arginine vasopressi
n in motion sickness. The effects of AVP analogs on motion sickness we
re investigated in squirrel monkeys. Two specific V-1 antagonists (SK&
F 100273 and SK&F 103561) and three mixed V-1/V-2 antagonists (SK&F 10
1926, SK&F 105494, and SK&F 104146-D) were tested on six highly suscep
tible monkeys. Intravenous injections of 200 ug of a v, antagonist abo
lished emesis in all six monkeys, and few prodromal symptoms remained
(latency to emesis > 120 minutes, P < .001). Mixed V-1/V-2 antagonists
foiled to abolish emesis in all monkeys. However, there was a slight
increase in the latency to the first bout of emesis/retching with the
mixed antagonists when compared with the baseline. The dose-response r
elationship and rate of onset of action of the V-1 antagonists (SK&F 1
00273) were explored. Latency to the first bout of emesis/retching inc
reased to about twice that of the baseline when half of the effective
antiemetic dose was used. The efficacy demonstrated by the specific V-
1 antagonists indicates that V-1 receptors may modulate emesis.