Startle responses, heart rate, and temperature in 5-HT1B receptor knockout mice.
Relative to wildtype mice, mice lacking 5-HT1B receptors (5-HT1B KO) exhibit exaggerated heart rate and body temperature responses to environmental stimuli. In contrast, acoustic startle reactivity is reduced in 5-HT1B KO mice. We combined heart rate and temperature measurement with startle response paradigms in order to elucidate this apparent contradiction. Habituation and footshock-induced sensitization paradigms modulate startle reactivity. Reduced startle reactivity and unaltered habituation in 5-HT1B KO mice were replicated. Heart rate and temperature were unaffected by startle stimuli, but increased markedly in response to transportation and handling procedures. Footshocks caused a mild startle-sensitization and tachycardia in both genotypes. The physiological hyper-reactivity in 5-HT1B KO mice is a subtle phenotypic difference that contrasts with the phenotypic decrease in startle reactivity.
Bouwknecht
J A
JA
Department of Psychopharmacology, Faculty of Pharmacy, Utrecht University, The Netherlands.
Hijzen
T H
TH
van der Gugten
J
J
Dirks
A
A
Maes
R A
RA
Hen
R
R
Geyer
M A
MA
Olivier
B
B
D000161:Acoustic Stimulation / Q000009:adverse effects; D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001831:Body Temperature / Q000235:genetics*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D004558:Electric Stimulation / Q000009:adverse effects; D006185:Habituation, Psychophysiologic / Q000502:physiology; D006339:Heart Rate / Q000235:genetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout / Q000502:physiology*; D010641:Phenotype; D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin / Q000172:deficiency* / Q000235:genetics; D013216:Reflex, Startle / Q000235:genetics*
D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin