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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.44 [2006] >
IJEB Vol.44(10) [October 2006] >
| Title: | Involvement of nitric oxide (NO) in the regulation of stress susceptibility and adaptation in rats |
| Authors: | Gulati, Kavita
Ray, Arunabha
Masood, Anbrin
Vijayan, V K |
| Keywords: | Adaptation
Emotionality
Nitric oxide
Stress |
| Issue Date: | Oct-2006 |
| Publisher: | CSIR |
| Abstract: | The present
study evaluated the regulatory role of nitric oxide (NO) in stress
susceptibility and adaptation in rats. Acute restraint stress (RS ×1) reduced
the number of entries and time spent in the open arms in the elevated plus maze
(EPM) test and raised plasma corticosterone levels. RS (×1)-induced
neurobehavioral suppression and raised corticosterone levels were attenuated by
pretreatment with the NO precursor, L-arginine (500 and 1000 mg/kg)and
unaffected or further aggravated by NO synthase inhibitor, L-NAME or
7-nitroindazole (10 and 50 mg/kg). Biochemical assay of plasma and brain
homogenates showed that these RS – induced behavioral and neuroendocrinal
changes were associated with lowered levels of plasma and brain total
nitrates/nitrites (NOx). L-Arginine attenuated the RS-induced suppression of
NOx levels in plasma and brain, whereas, the NO synthase inhibitors tended to
produce reverse effects. In the experiments involving repeated stress i.e. RS
(×5), exposure resulted in attenuation/reversal of (a) neurobehavioral
suppression in the EPM test and (b) lowered brain NOx, that was seen after RS
(×1). The RS (×5)-induced changes in EPM parameters and brain Nox were further potentiated
after L-arginine pretreatment, whereas, the NO synthase inhibitors were less
effective. Rats were screened as high and
low emotional in the open-field test, and high emotional rats showed greater(a)
behavioral suppression in the EPM,
(b) corticosterone responses (c) brain NOx suppression, and (d) cold-restraint
stress (CRS) induced gastric mucosal lesions as compared to their low emotional
counterparts. L-Arginine pretreatment was more effective in modulating the
above RS induced stress responses/markers in the high emotional group of rats.
Our data suggest that NO plays a differential role during exposure to acute and
repeated stress situations, and that the relationship between stress and
emotionality status may be under the regulatory influence of NO. |
| Page(s): | 809-815 |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.44(10) [October 2006]
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