Hepatoprotective activity of Achyrocline satureioides(Lam) D. C.

Aerial parts of Achyrocline satureioides(Lam) D. C. (Asteraceae) are used in folk medicine as infusions or decoctions for the management of several diseases including gastrointestinal and hepatic disorders. These data and the presence of flavonoids and caffeoyl derivatives have led us to study its hepatoprotective and choleretic activities. The hepatoprotective activity was evaluated in the bromobenzene- (BB-) induced hepatotoxicity model in mice through the measurement of the serum levels of alanine-aminotransferase (ALT) and aspartate transaminase (AST), thiobarbituric acid reacting substances (TBARS) and glutathione levels. The aqueous extract of the aerial parts of A. satureioides administered before BB, at the dose of 300 mg kg(-1)p.o., demonstrated significant inhibition (P< 0.01) in the BB increase of liver ALT and AST and in the BB-induced increase of liver TBARS content. Also it was able to significantly increase (P< 0.05) the depleted levels of liver glutathione. In addition, at the same dose, a significant increase (P< 0.01) in the bile flow of rats was found. The results obtained with the aqueous extract of A. satureioides support its use in popular medicine as a hepatoprotective and digestive agent, and the effects might be mediated through the antioxidant and choleretic activities.

AT-1 receptor and phospholipase C are involved in angiotensin III modulation of hypothalamic noradrenergic transmission.

1. We previously reported that angiotensin III modulates noradrenergic neurotransmission in the hypothalamus of the rat. In the present work we studied the effects of angiotensin III on norepinephrine release and tyrosine hydroxylase activity. We also investigated the receptors and intracellular pathways involved in angiotensin III modulation of noradrenergic transmission. 2. In rat hypothalamic tissue labeled with [3H]norepinephrine 1, 10, and 100 nM and 1 microM losartan (AT1 receptor antagonist) had no effect on basal neuronal norepinephrine release, whereas 10 and 100 nM and 1 microM losartan partially diminished norepinephrine secretion evoked by 25 mM KCl. The AT2 receptor antagonist PD 123319 showed no effect either on basal or evoked norepinephrine release. The increase in both basal and evoked norepinephrine output induced by 1 microM angiotensin III was blocked by 1 microM losartan, but not by 1 microM PD 123319. 3. The phospholipase C inhibitor 5 microM neomicin inhibited the increase in basal and evoked norepinephrine release produced by 1 microM angiotensin III. 4. Tyrosine hydroxylase activity was increased by 1 microM angiotensin III and this effect was blocked by 1 microM LST and 5 microM neomicin, but not by PD 123319. On the other hand, 1 microM angiotensin III enhanced phosphatidyl inositol hydrolysis that was blocked by 1 microM losartan and 5 microM neomicin. PD 123319 (1 microM) did not affect ANG III-induced phosphatidyl inositol hydrolysis enhancement. 5. Our results confirm that angiotensin III acts as a modulator of noradrenergic transmission at the hypothalamic level through the AT1-phospholipase C pathway. This enhancement of hypothalamic noradrenergic activity suggests that angiotensin III may act as a central modulator of several biological processes regulated at this level by catecholamines, such as cardiovascular, endocrine, and autonomic functions as well as water and saline homeostasis.

Antinociceptive effect of some Argentine medicinal species of Eupatorium.

Eupatorium laevigatum, E. arnottianum and E. subhastatum, plants used in Argentine folk medicine for the treatment of inflammation and pain related problems, were evaluated for analgesic activity. The infusions of these species (500 mg/kg, p.o.) produced a reduction in the number of stretches of 46.6%, 41.5% and 35.6% respectively, in the acetic acid induced writhing test. This antinociceptive effect of the infusions was not reversed by pretreatment with naloxone. The infusions studied did not produce antinociceptive effects when assayed in the hot plate test. These results suggest that the analgesic activity is exerted by a mechanism unrelated to interaction with opioid systems.