PT  - JOURNAL ARTICLE
AU  - Kulikov, Alexander
AU  - Aguerre, Sylvie
AU  - Berton, Olivier
AU  - Ramos, Andre
AU  - Mormede, Pierre
AU  - Chaouloff, Francis
TI  - Central Serotonergic Systems in the Spontaneously Hypertensive and Lewis Rat Strains that Differ in the Elevated Plus-Maze Test of Anxiety
DP  - 1997 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 775--784
VI  - 281
IP  - 2
4099  - http://jpet.aspetjournals.org/content/281/2/775.short
4100  - http://jpet.aspetjournals.org/content/281/2/775.full
SO  - J Pharmacol Exp Ther1997 May 01; 281
AB  - The spontaneously hypertensive (SHR) and Lewis (LEW) strains differ in numerous behavioral tests, including the elevated plus-maze. In keeping with the crucial role of central serotonin (5-HT) in anxiety, we checked for strain differences regarding several determinants of 5-HT activity. In addition to confirming that LEW rats displayed anxious behaviors in the plus-maze compared with SHR, we found that in vitro, central tryptophan hydroxylase activity was higher in LEW rats than in SHR. However, ex vivo studies in midbrains and hippocampi revealed that neither 5-HT synthesis nor 5-HT and 5-hydroxyindoleacetic acid levels differed between strains. [3H]8-Hydroxy-2-(di-n-propylamino)tetralin binding at midbrain 5-HT1A autoreceptors and hippocampal 5-HT1A postsynaptic receptors, [3H]ketanserin binding at cortical and striatal 5-HT2A receptors and [3H]citalopram binding at midbrain and hippocampal 5-HT transporters did not vary between strains. The inhibition of 5-HT synthesis by 5-HT1A autoreceptor stimulation was similar in both strains. Forepaw treading and flat body posture after 5-HT1A postsynaptic receptor stimulation were higher and lower, respectively, in SHR than in LEW rats. Last, 1-(4-iodo-2,5-dimethoxy-phenyl)-2-aminopropane- and quipazine-elicited head shakes, a 5-HT2A receptor-mediated response, were increased in the SHR strain compared with the LEW strain; on the other hand, 1-(3-chlorophenyl)piperazine triggered similar 5-HT2B/2C receptor-mediated decreases in motor activity in the two strains. This study shows that although the low-anxiety (SHR) and high-anxiety (LEW) strains vary in some aspects of 5-HT function, key components such as the 5-HT1A autoreceptors are not different. The American Society for Pharmacology and Experimental Therapeutics