Sensory and sensorimotor gating-disruptive effects of apomorphine in Sprague Dawley and Long Evans rats.
BACKGROUND
Rat strains differ in sensitivity to the disruptive effects of dopamine agonists on sensorimotor gating, measured by prepulse inhibition (PPI) of startle. For example, Sprague Dawley (SD) rats are more sensitive to PPI-disruptive effects of apomorphine (APO) compared to Long Evans (LE) rats; F1 (SDxLE) and N2 generations exhibit intermediate phenotypes. We reported that APO increased S2/S1 ratios and reduced S1 amplitudes of the N40 event-related potential (ERP) in SD rats, suggesting that it reduced sensory gating and/or sensory registration. Here, we investigated whether SD and LE rats differ in sensitivity to APO effects on N40 gating or amplitude.


METHODS
PPI and N40 gating were assessed contemporaneously in male SD and LE rats after APO, in a 4-day within-subject design.


RESULTS
Compared to SD rats, LE rats were less sensitive to the PPI-disruptive effects of APO. APO increased S2/S1 ratios paralleled by a dose-dependent reduction in S1 amplitude; SD and LE rats did not differ significantly in this measure. No clear relationship was evident between APO effects on PPI and N40 gating, nor between APO effects on startle magnitude and S1 amplitude, across strains.


CONCLUSIONS
SD and LE rats differ in their sensitivity to the disruptive effects of dopamine receptor activation on sensorimotor gating (PPI) but not sensory gating (N40 suppression) or sensory registration (S1 amplitude). These data suggest differences in both the neural and genetic regulation of dopamine agonist effects on these measures.
Breier
Michelle R
MR
Department of Psychiatry, University of California, San Diego School of Medicine, La Jolla, CA 92093-0804, USA.
Lewis
Brittanni
B
Shoemaker
Jody M
JM
Light
Gregory A
GA
Swerdlow
Neal R
NR
D000161:Acoustic Stimulation / Q000379:methods; D000704:Analysis of Variance; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D018491:Dopamine Agonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology; D008297:Male; D010641:Phenotype; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D013216:Reflex, Startle / Q000187:drug effects*; D055139:Sensory Gating / Q000187:drug effects* / Q000235:genetics*; D013045:Species Specificity
D018491:Dopamine Agonists; D001058:Apomorphine