Biomedical subjects
Publications and source records attributed to A R Zahran.
We present 2 cases of Peyronie's disease in patients with scleroderma. This association is uncommon, and our patients' symptoms and disease course differed from that typical for Peyronie's disease. We suggest a more conservative approach when treating patients whose penile curvature is associated with a systemic disease such as scleroderma.
Erectile function was assessed 6 weeks following uni- and bilateral injections of 6-hydroxydopamine in the substantia nigra nucleus of the brain. Behavioral apomorphine-induced penile erections were reduced (5/8) and increased (3/8) in uni- and bilateral lesioned animals. Intracavernous pressures, following electrical stimulation of the cavernous nerve, decreased in lesioned animals. Lesions of the substantia nigra were confirmed by histology. Concentration of dopamine and its metabolites were decreased in the striatum of substantia nigra lesioned rats. Lesions of the substantia nigra are therefore associated with erectile dysfunction in rats and may serve as a model to study erectile dysfunction in Parkinson's disease.
The objective of this present study is to establish a model in the rat for the study of female clitoral and vaginal vascular changes during sexual excitation. A laser Doppler was used to measure blood flow changes following clitoral and pelvic plexus nerve stimulations. Results show an increase in clitoral blood flow following clitoral nerve (df1 = 12, df2 = 108, F = 21.4, P < 0.001) and pelvic plexus nerve stimulations (n = 3). A vaginal blood flow increase is also observed following pelvic plexus nerve stimulations (df1 = 12, df2 = 108, F = 4.75, P < 0.001). The female rat can therefore be used as a model for the study of the physiology, pharmacology and sexual dysfunction relating to blood flow in clitoral and vaginal tissue.
PURPOSE: We examined whether N-methyl-D-aspartate (NMDA), amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) or trans-1-amino-1,3-cyclo-pentadicarboxylic acid (ACPD) increase intracavernous pressures when injected in the paraventricular nucleus of the hypothalamus. MATERIALS AND METHODS: Sprague-Dawley rats weighing 250 to 300 gm. were anesthetized with pentobarbital and placed in a stereotaxic apparatus after catheterization of the carotid artery and insertion of a 25 gauge needle in the corpus cavernosum. Both catheters were coupled to pressure transducer systems. Electrical stimulations with glass tungsten microelectrodes and chemical injections with a 0.5 microl. syringe were done in the paraventricular nucleus. At the end of each experiment rats were perfused with saline and 10% formalin solutions. Brains slices 16 microm. thick were mounted and stained with cresyl violet to identify chemical and electrical stimulation sites. RESULTS: Electrical stimulations of the paraventricular nucleus increased intracavernous pressure from 15.5 +/- 5.7 to 50.02 +/- 20.4 cm. H2O in 10 rats (p <0.001) and decreased central pressure in 10 (p <0. 001). Intracavernous pressure increased from 17.2 +/- 5.26 to 60.6 +/- 14.36 cm. H2O with NMDA, 26.0 +/- 8.9 to 49.6 +/- 12.2 cm. H2O with AMPA and 18.0 +/- 2.3 to 41.0 +/- 22.68 cm. H2O with ACPD when injected in the paraventricular nucleus of 5 rats (analysis of variance 12.18, df 3, p <0.007). Mean delays and durations varied between 3.6 to 4.0 and 5.6 to 7.0, respectively, and were similar for all agonists (analysis of variance not significant). CONCLUSIONS: Glutamate receptor subtypes NMDA, ACPD and AMPA cause an increase in intracavernous pressure when injected in the paraventricular nucleus. Therefore, increases in intracavernous pressure following injection of glutamate must be initiated by the synergistic or additive effects of all of these receptor subtypes.