Effect of Pueraria tuberosa on Cold Immobilization Stress Induced Changes in Plasma Corticosterone and Brain Monoamines in Rats

The study was carried out to establish the anti-stress effect of Pueraria tuberosa in relation to the levels of plasma corticosterone and norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in whole brain and hypothalamus and compared with Withania somnifera (adaptogen). Adult male Wistar rats pretreated with 70% hydroethanolic extract of P. tuberosa tuber ischolar_main (PTE) at the doses of 50, 100, 200 and 400 mg/kg, for 5 consecutive days. W. somnifera rhizome extract (WSE) at 100 mg/kg was used as reference drug. The rats were subjected to cold immobilization stress (IS) for 2 h. Thereafter, the animals were sacrificed and ulcer formation in gastric mucosa was noted. Weights of adrenals and spleens were also taken. Further, plasma corticosterone levels were estimated by spectrophotoflurometrically. Simultaneously, brain monoamines like, NE, DA and 5-HT were determined in whole brain and hypothalamus region HPLC electrochemical detector. IS for 2 h damaged the gastric mucosal layers, enhanced plasma corticosterone levels and increase adrenal glands and spleen weight. Further, IS elevated NE, DA and 5-HT levels both in whole brain and hypothalamus. PTE significantly protected the gastric mucosa, lowered corticosterone level in blood and negated the hypertrophy of adrenals and spleen. PTE (200 and 400 mg/kg) and WSE (100 mg/kg) significantly decreased IS elevated NE, DA and 5-HT both in whole brain and hypothalamus. These data suggest that anti-stress effect of Pueraria tuberosa may be modulated by monoaminergic system.