Objective To detect and locate anatomically peripheral dopamine D1 and D2 receptors in rat cavernosa, as dopamine is important in sexual drive and penile erection through receptors located in the central nervous system. Materials and methods Corpora cavernosa were obtained from Sprague-Dawley rats; total RNA and membrane proteins were extracted and cryostat sections prepared. The rat brain hypothalamus was used as a control for dopamine D1 and D2 receptors. The presence and expression of peripheral dopamine D1 and D2 receptor mRNAs in rat corpus cavernosa was assessed using reverse transcription and polymerase chain reaction (RT-PCR), and Northern blot hybridization using 32 P-UTP-labelled RNA probes. Concurrently, corresponding proteins from D1 and D2 receptors were assayed and detected by a Western blotting technique. The anatomical location of dopamine D1 and D2 receptor mRNAs in rat penile tissues was identified by in situ hybridization using 35 S-UTP-labelled RNA probes in cryostat sections.Immunohistochemical staining was used to locate peripheral dopamine D1 and D2 receptor proteins in rat corpora cavernosa. Results Dopamine D1 and D2 receptor gene expression was detected in rat corpora cavernosa. In situ hybridization signals for dopamine D1 and D2 receptor mRNAs were localized to corpus cavernosal tissues and dorsal vessels in the rat penis. Western blot analyses showed peripheral dopamine D1 and D2 receptor proteins in rat corpora cavernosa. Immunohistochemically, peripheral dopamine D1 and D2 receptor proteins were detected in dorsal nerves, dorsal vessels and corpus cavernosal smooth muscle of the rat penile tissues. Conclusions Peripheral dopamine D1 and D2 receptors are present in the corpora cavernosa of rats. The functional significance of these receptors and signal transduction pathways in modulating the vascular tone of the penis warrants further investigation.

Dopamine, an established neurotransmitter in the central nervous system, is recognized for its role in penile erection and ejaculation in rats. However, its complete mechanism of action in the genitourinary tract is unknown. The objective of this study was to investigate the existence and expression of peripheral dopamine D1 and D2 receptor messenger RNAs (mRNAs) and corresponding proteins in rat and human seminal vesicles. The seminal vesicle tissues of male Sprague-Dawley rats and human radical prostatectomy specimens were used to extract total RNA and proteins, and to prepare slide sections. Rat hypothalamus tissue served as a control for dopamine D1 and D2 receptors. Testing for the presence and expression of peripheral dopamine D1 and D2 receptor mRNAs in rat and human seminal vesicle tissues was performed by reverse transcription-polymerase chain reaction. Western blotting was used to detect corresponding proteins of D1 and D2 receptors. Immunohistochemical staining using rabbit antipeptide polyclonal antibodies was employed to identify and anatomically localize dopamine D1 and D2 receptor proteins in rat and human seminal vesicles. Dopamine D1 and D2 receptor transcripts were detected in both human and rat seminal vesicle tissues. Western blot analysis demonstrated that peripheral dopamine D1 and D2 receptor proteins exist in both human and rat seminal vesicle tissues. Immunohistochemical analysis demonstrated the localization of peripheral dopamine D1 and D2 receptors to the smooth muscle layer of human and rat seminal vesicles. The results of this study demonstrate that peripheral dopamine D1 and D2 receptors are present in the seminal vesicle tissue in both rats and humans. Although these results suggest that seminal emission may be mediated in part by the stimulation of peripheral dopamine receptors located in the seminal vesicles, the functional significance of dopamine in male reproductive tract has yet to be fully defined. E jaculation is governed by 3 interacting levels of the nervous system: the modulator influence, which originates from the supraspinal level; interaction at the spinal cord level; and sensory input, which determines the amplitude of the sacral reflex. These events occur reflexively, and require coordination of the autonomic and somatic nervous systems. The precise neurophysiological mechanism that controls these reflexes is not well understood. It has been suggested that the serotonergic and dopaminergic systems have both inhibitory and excitatory influences on penile erection and ejaculation at the supraspinal level (Hull et al, 1992;Olivier et al, 1998).Dopamine is an endogenous catecholamine that influences many cellular activities, including behavior, hormone synthesis and release, blood pressure, and intracellular ion transport. The actions of dopamine on target tissues are mediated by cell surface receptors. Recently, atCorrespondence to: Wayne J.G. Hellstrom, MD, FACS, Professor of Urology, Tulane University Health Sciences Center, 1430 Tulane Ave, SL-42, New Orl...

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Proximal tubule cell migration is likely a critical early event in recovery from acute renal injury with spreading and migration of cells to cover denuded basement membrane. Growth factors (GFs), including epidermal (EGF), hepatocyte (HGF) and insulin-like growth factor-1 (IGF-1), may play an important role in repair. We have previously shown that each stimulates migration in immortalized human proximal renal tubule cells under control conditions. We now investigated the effect of GFs on migration of these cells after oxidant stress. The cells were cultured in serum- and growth factor-free medium. Confluent cultures were exposed to H2O2 for 1 hour, washed, then scraped with a pipette tip. GFs were added and the area of migration was measured over the next 6 hours. After oxidant stress with 750 μM peroxide, migration decreased to 60% of control (uninjured, no GFs) values. After EGF and HGF migration returned nearly to control values while IGF-1 actually stimulated migration to 131 ± 12 (SEM) % of control values. Adding EGF or HGF to IGF-1 further stimulated migration to 163 ± 16% and 166 ± 13% of control values respectively, representing an increase of ˜ 2.7× over peroxide injured cells (with no GFs). EGF and HGF were not additive. With more severe injury (1.2-1.5 mM H2O2), there was modest stimulation by HGF and IGF-1. There was still some additivity of EGF and HGF with IGF-1, averaging ˜ 1.5× peroxide alone, but values remained depressed compared to uninjured cells not treated with GFs. In summary, the GFs examined stimulated human proximal tubule cell migration after oxidant stress, with IGF-1 being the most potent, especially in combination with EGF or HGF. The stimulation was most pronounced with mild injury. We conclude that the stimulation of migration by growth factors may contribute to their beneficial effect after acute injury.

to June 30, 2004, were reviewed and data were collected. Results: 486 infants of 30-33 weeks gestation had screening cranial US performed. IVH occurred in 22 of 486 (4.5%). Of the 22 infants, 4 infants had significant IVH (grade III and/or grade IV). Of the 4 infants with significant IVH, 2 were 30 weeks and 2 were 31 weeks gestation. All 4 infants had either significant risk factors for brain injury (abruption, asphyxia) or clinical symptoms (seizures) that would warrant US during their hospital course. Of the 486 infants who had US, 5 additional infants (1%) had PVL, and 2 of these 5 had risk factors (abruption, shock) that warranted obtaining a sonogram. There was a statistically significant trend towards fewer abnormal sonograms from 33 weeks to 30 weeks gestation (p = .04).