estimated collagen-stimulated whole blood platelet and 0.98 ± 0.10 mg, respectively, vs. VEH 0.94 ± 0.09 mg; aggregation ex vivo in thrombotic rats. The substances * p < 0.05, n = 5–10), prolonged PT (19.46 ± 0.56* s were administered per os, twice daily for 3 days in and 18.63 ± 0.37 s vs. VEH 18.08 ± 0.20 * p < 0.05) doses of 0.17 mmol/kg each in volume of 2 ml/kg in and inhibited platelet aggregation (72.3 ± 7.8% and distilled water. Mean blood pressure (MBP) was 90.0 ± 8.5%, respectively, vs. VEH 100%; p < 0.05, measured directly in left carotid artery in anesthetized n = 5–10). Also NaNO2 decreases MBP (maximal rats acute treated (intravenously) with NaNO2 or delta MBP ~50 mmHg) while NaNO3 is off any NaNO3 during the measurement. The prothrombin hypotensive effect. time (PT), Activated Partial Thromboplastin Time To conclude, our comparative study shown, that in (APTT), QUICK index and fibrinogen level were also rat nitrites are active, while nitrates do not exert anti- determined. thrombotic and hypotensive activity. The metabolic We have shown, that NaNO2, but not NaNO3 difference seems to be responsible for different effects decreases arterial thrombus weight (0.49 ± 0.11* mg of studied substances on hemostasis.

Influence of mecamylamine and bupropion on nicotine-induced memory improvement in novel object recognition in mice

Marta Kruk-S³omka1, Agnieszka Michalak1, Barbara Budzyñska1, Gra¿yna Bia³a1

Chair and Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, ChodŸki 4A, PL 20-093 Lublin, Poland

The aim of the study was to investigate the involve- ing the second and the third session, comparing to an ment of the cholinergic receptors ligands in the appropriate control group. It indicates that nicotine memory-related responses induced by nicotine in administered acutely can improve memory in mice. mice. Memory performance was examined using the Additionally, the acute injection of the nicotinic ace- novel object recognition (NOR) test. The NOR test is tylcholine receptors antagonists – mecamylamine (0.5 based on the natural tendency of rodents to explore and 1 mg/kg) and bupropion (5 and 10 mg/kg), prior preferentially a novel object instead of a familiar ob- to injections of nicotine (0.035 mg/kg), significantly ject. During the first session the tested animal was al- prevented nicotine-induced memory improvement lowed to explore freely two identical objects placed in during the second and the third session. the experimental arena. During the next session, The results of this study help to understand neu- which was conducted after the delay period of 30 min ronal mechanisms for cholinergic system of memory (the second session) or 24 h (the third session), the processes. The more detailed is our knowledge in this animal was returned to the arena, where one of the fa- matter, the more effective pharmacotherapies for miliar objects had been replaced by a new one. The memory impairment-like treatment of human disor- mice injected with nicotine (0.035 and 0.175 mg/kg, ders, in which cholinergic pathways have been impli- free base, sc) before the first session spent more time cated, are within our reach. exploring the novel object than the familiar one dur-

58 Pharmacological Reports, 2013, 65, suppl.