अमूर्त

The impact of sildenafil citrate on neurotransmitter amino acids levels in brain tissue of albino rat.

Hani M.Abd Elsalam

Purpose: Sildenafil citrate is an active cGMP-specific phosphodiesterase type 5 (PED 5) inhibitor that is successful in the therapy of male erectile dysfunction. There are no previous studies recorded the chronic effect of sildenafil or its possibly related neurochemical changes, but mainly they related their finding to sildenafil citrate associated behavior alternations. In this work, brain neurochemical alterations (excitatory and inhibitory neurotransmitters amino acids) associated with chronic administration of sildenafil citrate using male albino rats were investigated. Materials and methods: Rats were categorized into two groups (n=8); group 1 received saline (0.5 ml/kg) and group 2 received single dose of sildenafil citrate (Viagra, Pfizer Inc.) dissolved in saline and administered at a dose of 10 mg/kg i.e. (0.5 ml) to rats in the treated group every 3 days for 19 injections. All rats were sacrificed 24 h after the last injection. Brain areas’ homogenate for neurotransmitters were evaluated by HPLC. Results: It has been found that the chronic i.e. injection of sildenafil citrate caused a pronounced increase in the levels of both excitatory and inhibitory amino acids in most of the brain regions studied. The maximal increases in the concentrations of excitatory (glutamate and aspartate) and inhibitory (GABA and glycine) amino acids were obtained in the cerebellum. Glutamine and alanine concentrations recorded the maximal increases in cerebral hemisphere of the rat brain. While the maximal increases in the levels of asparagine was recorded in the olfactory lobe. On the other hand, the maximal decreases in the excitatory (glutamine and asparagine) and the inhibitory (glycine and alanine) amino acids were obtained in the pons-medulla, while taurine concentration showed a significant increases in this area of the rat brain. Conclusion: Our results explained the effect of sildenafil on central neural pathways that are related to the control of sexual arousal (erection). According to extreme use of sildenafil citrate and in addition to the results of the present study we supposed that it is very significant to increase the papers that are related to the influence of the chronic administration of Viagra.