Further evidence for the role of nitric oxide in maternal aggression: effects of L-NAME on maternal aggression towards female intruders in Wistar rats.

It has been shown that nitric oxide (NO) increases aggression in male mice, whereas it decreases aggression in lactating female mice and prairie voles. It is also known that aggression can be exhibited at different levels in rodent species, strain or subtypes. The aims of this study were to investigate the proportion of aggressiveness in Wistar rats, the effect of intraperitoneally administered nonspecific nitric oxide synthase (NOS) inhibitor L-NAME (NG-nitro L-arginine methyl ester) on maternal aggression towards female intruders, and whether these effects are due to NO production or not. Rats were given saline intraperitoneally on the postpartum Day 2 and aggression levels were recorded. The same rats were given 60 mg/kg L-NAME or D-NAME (NG-nitro D-arginine methyl ester) on the postpartum Day 3 and their effects on aggression levels were compared to saline. While L-NAME administration did not cause any differences in the total number of aggressive behavior, aggression duration and aggression intensity, it reduced the proportion of animals showing aggressive behavior. In addition, the latency of the first aggression was significantly increased by L-NAME. In the D-NAME group, however, no significant change was found. Our results have shown that L-NAME reduces maternal aggression towards female intruders in Wistar rats through inhibition of NO production. These results suggest that the role of NO in offensive and defensive maternal aggression shares neural mechanisms.

Tumour necrosis factor alpha -308G/A gene polymorphism: lack of association with knee osteoarthritis in a Turkish population.

OBJECTIVE: To study the association between TNFalpha-308 G/A polymorphism and susceptibility to and severity of knee osteoarthritis in a Turkish population. METHODS: Genomic DNA was obtained from 151 patients with knee osteoarthritis and 84 ethnically matched healthy controls. Polymerase chain reaction-restriction fragment length analysis was used to identify G/A polymorphism at position -308 in the promoter region. Genotype distributions and allelic frequencies of TNFalpha-308 G/A polymorphism were compared between osteoarthritis patients and controls. Thereafter, this association was investigated between patients and controls of the same sex. In addition, the standard Kellgren-Lawrence grading score and the Turkish version of the Western Ontario and McMaster Universities Osteoarthritis Index were used to assess the radiological and functional severity of the disease and their relationship with the TNFalpha-308 gene polymorphism was investigated. RESULTS: Genotype distribution and allelic frequencies of -308 G/A polymorphism in the TNFalpha gene did not differ significantly between patients with knee osteoarthritis and controls (p>0.05). Moreover, there were no significant differences between patients and controls of the same sex (p>0.05). In addition, no association was observed between the radiological and functional severity of the disease and TNFalpha-308 G/A polymorphism (p>0.05). CONCLUSION: These findings suggest that the examined polymorphism in the TNFalpha gene does not contribute to susceptibility to or severity of knee osteoarthritis in the Turkish population.