Effects of N-Nitro-L-Arginine on Isolated Rabbit Afferent Arterioles

Abstract

ABSTRACT-Paeoniflorin, a major constituent of peony root, has been demonstrated to attenuate the radial maze performance deficit produced by scopolamine. In the present study, to investigate the possible involvement of ~-adrenergic systems in the paeoniflorin antagonism of the scopolamine deficit, the effects of two ~-adrenoceptor antagonists, propranolol and atenolol, on the paeoniflorin effect were examined in male Wistar rats. Paeoniflorin (1 mg/kg, p.o.) significantly attenuated the scopolamine HBr (0.3 mg/kg, i.p.) induced deficit in the choice accuracy in radial maze performance without changing the running time pro longed by scopolamine. Neither D,L-propranolol HCl, a lipophilic p-antagonist, at 3 mg/kg, i.p. nor atenolol, a hydrophilic p1-antagonist that is known to hardly ever cross the blood-brain barrier, at 1 mg/kg, i.p. impaired maze performance by itself or aggravated the scopolamine-induced deficit in radial maze per formance. Both antagonists, however, completely blocked the antagonizing effect of paeoniflorin on the scopolamine deficit. These data suggest that the 3-adrenergic systems, especially peripheral ~1-adrenergic systems, are involved in the antagonizing effect of paeoniflorin on the scopolamine deficit in radial maze per formance in rats.

Determination of paeoniflorin in rat hippocampus by high-performance liquid chromatography after intravenous administration of Paeoniae Radix extract

“…Moreover, many studies indicated cognition-enhancing effects of Paeoniae Radix extract and/or paeoniflorin [12][13][14][15][16][17][18]. In brief, it was reported that the oral administration of the aqueous extract of peony root and paeoniflorin dose-dependentiy ameliorates spatial cognitive impairment caused by scopolamine in rats [12,13] via reversing muscarinic M 1 -receptor antagonist (scopolamine)-induced inhibition of long-term potentiation (LTP), a prolonged form of synaptic plasticity in the hippocampal region [14].…”

Solid-phase extraction–liquid chromatographic method for the determination and pharmacokinetic studies of albiflorin and paeoniflorin in rat serum after oral administration of Si–Wu decoction

“…1), the major constituents in R. paeoniae and Si-Wu decoction, are water-soluble compounds isolated from the roots of Paeonia lactifloria [2,3]. Paeoniflorin has been reported to exhibit anti-coagulant [4], neuromuscular blocking [5][6][7], immunoregulating [8], cognition-enhancing [9][10][11] and anti-hyperglycemic effects [12]. Pharmacological investigation showed that paeoniflorin was one of the major active principles of Si-Wu decoction [13].…”

Kinetic distribution of paeoniflorin in cortex of normal and cerebral ischemia-reperfusion rats after intravenous administration ofPaeoniae Radix extract

“…PF also improved learning deficit of aged rats (Ohta et al, 1994). Many studies have indicated cognition-enhancing effects of Paeoniae Radix extract and/or PF (Ohta et al, 1993a(Ohta et al, -c, 1994Watanabe, 1997;Tabata et al, 2000). Oral administration of the aqueous extract of peony root and PF could reduce learning impairment and dose-dependently ameliorated spatial cognitive impairment caused by scopolamine in rats (Ohta et al, 1993b, c).…”