Dr. José Eguibar - Universidad Autónoma de Nayarit

II International Symposium on Perspectives in Neuroimmunoendocrinology
II Congreso Nacional de la Sociedad Mexicana de
Neuroinmunoendocrinología
THE HIGH-YAWNING RATS SHOWED AN ANXIETY PHENOTYPE IN
DIFFERENT BEHAVIORAL TESTS AND DIFFERENT PATTERN OF
CORTICOSTERONE SECRETION
Eguibar Jose R., Cortes Carmen, Trujillo Angélica, and Uribe Carlos.
Research Office, VIEP, Institute of Physiology and Biology School. Benemerita Universidad
Autonoma de Puebla. Apdo. Postal 5-66. Puebla, Pue. C.P. 72430. México
We selectively bred two sublines from Sprague-Dawley rats, one with a highyawning (HY) frequency with a mean of 20 yawns/h, and the low-yawning (LY)
with just 2 yawns/h. HY rats ambulated more in the open-field arena (OFA)
respect to LY suggesting different emotional reactivity. The aim of these studies
is to analyze with detail the anxiety behavior in the OFA and in the elevated-plus
maze
(EPM),
as
well
as
measuring
corticosterone
(Cort)
and
adrenocorticotrophic (ACTH) hormone plasma levels using ELISA techniques.
The results showed that HY rats showed more thigmotaxis, that is ambulation
close to the walls of the OFA and avoid the central square, the opposite happen
in the LY rats (P<0.05). HY rats in the EPM showed lower number of entrances
and hence time spent in the open arms respect to LY rats (P<0.05). ACTH levels
were higher in the HY respect to LY rats (P<0.05) and with slower clearance of
II International Symposium on Perspectives in Neuroimmunoendocrinology
II Congreso Nacional de la Sociedad Mexicana de
Neuroinmunoendocrinología
Cort peak after restriction stress. This endocrine parameters are associated with
heavier adrenal glands in the HY respect to LY rats (P<0.05).
These results support that HY animals are more anxious and has over activation
of the hypothalamic-hypophysis-adrenal gland axis suggesting is an adequate
animal model of anxiety with over stimulate adrenal gland activity.
Supported by CONACYT grant No. 243247 to JRE and by VIEP-BUAP DES
Salud to JRE and CC.