Effect of immobilization stress on brain polyamine levels in spontaneously hypertensive and Wistar-Kyoto rats.
The present study aimed to compare the basal brain polyamine levels and stress-induced brain polyamine level changes in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. For immobilization stress, both strains underwent acute (3 h per day immobilization for 2 days), chronic (3 h per day immobilization for 15 consecutive days), or no immobilization stress (control group). Basal putrescine (PU) levels in frontal cortex and hippocampus of SHR (11.03 +/- 0.81 and 11.36 +/- 0.33 nmol/g tissue, respectively) were significantly higher than WKY rats (6.90 +/- 1.44 and 7.82 +/- 0.71 nmol/g tissue, respectively). However, there were no strain differences in basal spermidine and spermine levels between the two. After acute stress, the PU levels in frontal cortex and hippocampus (15.99 +/- 0.45 and 14.10 +/- 0.95 nmol/g tissue, respectively) were significantly increased in SHR as compared to the non-stressed SHR (11.03 +/- 0.81 and 11.36 +/- 0.33 nmol/g tissue, respectively). In WKY rats, the PU level was significantly increased by acute stress in frontal cortex (11.68 +/- 1.12 nmol/g tissue) as compared to the non-stressed WKY (6.90 +/- 1.44 nmol/g tissue). After chronic stress, the PU levels in frontal cortex and hippocampus of SHR (12.44 +/- 0.54 and 11.34 +/- 0.66 nmol/g tissue, respectively) significantly decreased as compared to acute-stressed groups (15.99 +/- 0.45 and 14.01 +/- 0.95 nmol/g tissue, respectively). In WKY rats, after chronic stress, the PU level was significantly decreased in frontal cortex (5.73 +/- 0.36 nmol/g tissue) as compared to acute-stressed groups (11.68 +/- 1.12 nmol/g tissue). The PU levels in frontal cortex and hippocampus of acute-stressed (15.99 +/- 0.45 nmol/g tissue and 14.10 +/- 0.95 nmol/g tissue, respectively) and chronic-stressed (12.44 +/- 0.54 and 11.34 +/- 0.66 nmol/g tissue, respectively) SHR were significantly higher than acute-stressed (11.68 +/- 1.12 and 9.76 +/- 0.45 nmol/g tissue, respectively) and chronic-stressed (5.73 +/- 0.36 and 8.44 +/- 0.71 nmol/g tissue, respectively) WKY rats. The present study provides the higher basal PU level and stress-induced PU response in SHR as compared to WKY rats may be related to enhanced response of hypothalamic-pituitary-adrenocortical axis and sympathetic influence that may significantly contribute to the development of hypertension in SHR.
Sohn
Hyung Seok
HS
Department of Psychiatry, School of Medicine, Keimyung University, 194 Dongsan dong, Taegu, 700-712 South Korea
Park
Young Nam
YN
Lee
Seong Ryong
SR
D000208:Acute Disease; D000818:Animals; D015317:Biogenic Polyamines / Q000378:metabolism*; D001921:Brain / Q000254:growth & development / Q000378:metabolism* / Q000503:physiopathology; D002908:Chronic Disease; D005625:Frontal Lobe / Q000254:growth & development / Q000378:metabolism / Q000503:physiopathology; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism / Q000503:physiopathology; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D007030:Hypothalamo-Hypophyseal System / Q000254:growth & development / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D011700:Putrescine / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012149:Restraint, Physical; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013312:Stress, Physiological / Q000378:metabolism* / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000254:growth & development / Q000378:metabolism* / Q000503:physiopathology
D015317:Biogenic Polyamines; D013096:Spermine; D013095:Spermidine; D011700:Putrescine