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Spontaneous slow wave activity in aging guinea pig prostates
Abstracts
their receptors (OX1R and OX2R) are distributed in neural tissue and brain regions involved in the autonomic and neuroendocrine control. Within the hypothalamus, orexin fibers and orexin receptors, especially OX2R, are found extensively in the paraventricular nucleus (PVN) of the hypothalamus. The PVN is an integrative center of the autonomic nervous system and the neuroendocrine system. Thus, orexins may play a role in the regulation of cardiovascular and autonomic nervous systems. We demonstrated that intracerebroventricular(i.c.v.) administration of orexins increase the arterial blood pressure(ABP), heart rate(HR), renal sympathetic nerve activity, and plasma catecholamine concentrations in conscious rats. In addition, bath application of orexins excited PVN neurons of brain slice preparation, in dosedependent manner. In the present study, we examined the effects of orexin-A on the neural activities of the PVN in conscious freely-moving rats. Of the non-phasic (irregular) PVN neurons (n = 22) examined, orexin-A (i.c.v. 0.3 nmol) elicited excitation in 12 neurons, inhibition in 2 neurons and no response in 8 neurons, accompanied with increases in ABP and HR. Neurons that were affected by orexin-A were then further examined for their responses to perturbation in ABP and systemic administration of cholecystokinin-8 (CCK). The majority of neurons also showed responses to CCK, phenylephrine, or nitropurusside. The present studies suggest that PVN plays a role as one of the efferent pathways of orexin-A-induced activation of the sympathetic outflow, and orexins participate in the regulation of cardiovascular function and energy balance through the autonomic nervous system, particularly, under stress-related condition. doi:10.1016/j.autneu.2007.06.211
I-P-098 Spontaneous slow wave activity in aging guinea pig prostates Anupa Dey a, Dan-Thanh Nguyen a , Rick Lang b, Betty Exintaris a a Department of Pharmaceutical Biology, Victorian College of Pharmacy, Monash University, Parkville, Victoria, Australia b Department of Physiology, Monash University, Clayton, Victoria, Australia
123
Methods Prostate glands were removed from immature and aged guinea-pigs (900–1200 g) killed humanely. Saccular glands were pinned to the bottom of an organ bath, which was subsequently mounted on an inverted microscope stage and perfused with physiological saline solution. Standard intracellular membrane potential recording techniques were used. Results The time course of the spontaneous slow waves consisted of distinct depolarising transients with superimposed spike potentials. The frequency of the slow wave discharge was 5.9 ± 0.9 min−1. The average resting membrane potential was − 49.6 ± 4.2 mV followed by the depolarising component which had an amplitude of 6.9 ± 2.2 mV and an average of 2.9 ± 0.5 superimposed spike potentials. The L-type calcium channel blocker nifedipine (1 μM) reduced the frequency of slow waves from 6.3 ± 1.2 min−1 to 4.6 ± 1.7 min−1 (n = 3). In contrast the amplitude of the depolarising component was unaffected, although the superimposed spike potentials were abolished indicating that the depolarising component arises from a mechanism other than the opening of L-type calcium channels. Preliminary experiments were also conducted using the nitric oxide blocker, L-NAME (10 μM). Upon addition of L-NAME the frequency of slow waves increased, indicating that a tonic release of nitric oxide may also have a role in the modulation of this activity. Standard Transient Depolarisations (STDs), were often recorded in the presence and absence of slow wave activity (n = 6). The STDs occurred at a frequency 10.3 ± 2.0 min−1 and had an overall amplitude of 12.3 ± 1.51 mV. We have previously suggested that bursts of STDs may sum to generate the pacemaker potential which propagates to smooth muscle cells to form the depolarising component of the slow wave [1]. Conclusion Slow wave activity can be recorded in the aging guineapig prostate. The configuration of the prostatic slow wave in aging animals is similar to that recorded in younger animals. (1) Lang et al. (2006) Journal of Urology 175(1): p. 370–80.
Introduction and aims doi:10.1016/j.autneu.2007.06.212
The aging male has a risk of developing prostate specific conditions such as benign prostatic hyperplasia, a condition which is typically accompanied by urethral obstruction as a result of an increase in smooth muscle tone. We have previously reported that spontaneous slow wave activity underlies the spontaneous contractions which are likely to contribute to the smooth muscle tone of the prostate. This study aims to characterize the spontaneous slow wave activity in aging guinea pig prostates.
I-P-099 Postnatal downregulation of inhibitory neuromuscular transmission in ileal longitudinal muscle of guinea pigs Xiaochun Bian, Martin Carrasquillo, Joshua E. Burda Department of Pharmacology and Toxicology, Michigan State University; East Lansing, Michigan, USA
their receptors (OX1R and OX2R) are distributed in neural tissue and brain regions involved in the autonomic and neuroendocrine control. Within the hypothalamus, orexin fibers and orexin receptors, especially OX2R, are found extensively in the paraventricular nucleus (PVN) of the hypothalamus. The PVN is an integrative center of the autonomic nervous system and the neuroendocrine system. Thus, orexins may play a role in the regulation of cardiovascular and autonomic nervous systems. We demonstrated that intracerebroventricular(i.c.v.) administration of orexins increase the arterial blood pressure(ABP), heart rate(HR), renal sympathetic nerve activity, and plasma catecholamine concentrations in conscious rats. In addition, bath application of orexins excited PVN neurons of brain slice preparation, in dosedependent manner. In the present study, we examined the effects of orexin-A on the neural activities of the PVN in conscious freely-moving rats. Of the non-phasic (irregular) PVN neurons (n = 22) examined, orexin-A (i.c.v. 0.3 nmol) elicited excitation in 12 neurons, inhibition in 2 neurons and no response in 8 neurons, accompanied with increases in ABP and HR. Neurons that were affected by orexin-A were then further examined for their responses to perturbation in ABP and systemic administration of cholecystokinin-8 (CCK). The majority of neurons also showed responses to CCK, phenylephrine, or nitropurusside. The present studies suggest that PVN plays a role as one of the efferent pathways of orexin-A-induced activation of the sympathetic outflow, and orexins participate in the regulation of cardiovascular function and energy balance through the autonomic nervous system, particularly, under stress-related condition. doi:10.1016/j.autneu.2007.06.211
I-P-098 Spontaneous slow wave activity in aging guinea pig prostates Anupa Dey a, Dan-Thanh Nguyen a , Rick Lang b, Betty Exintaris a a Department of Pharmaceutical Biology, Victorian College of Pharmacy, Monash University, Parkville, Victoria, Australia b Department of Physiology, Monash University, Clayton, Victoria, Australia
123
Methods Prostate glands were removed from immature and aged guinea-pigs (900–1200 g) killed humanely. Saccular glands were pinned to the bottom of an organ bath, which was subsequently mounted on an inverted microscope stage and perfused with physiological saline solution. Standard intracellular membrane potential recording techniques were used. Results The time course of the spontaneous slow waves consisted of distinct depolarising transients with superimposed spike potentials. The frequency of the slow wave discharge was 5.9 ± 0.9 min−1. The average resting membrane potential was − 49.6 ± 4.2 mV followed by the depolarising component which had an amplitude of 6.9 ± 2.2 mV and an average of 2.9 ± 0.5 superimposed spike potentials. The L-type calcium channel blocker nifedipine (1 μM) reduced the frequency of slow waves from 6.3 ± 1.2 min−1 to 4.6 ± 1.7 min−1 (n = 3). In contrast the amplitude of the depolarising component was unaffected, although the superimposed spike potentials were abolished indicating that the depolarising component arises from a mechanism other than the opening of L-type calcium channels. Preliminary experiments were also conducted using the nitric oxide blocker, L-NAME (10 μM). Upon addition of L-NAME the frequency of slow waves increased, indicating that a tonic release of nitric oxide may also have a role in the modulation of this activity. Standard Transient Depolarisations (STDs), were often recorded in the presence and absence of slow wave activity (n = 6). The STDs occurred at a frequency 10.3 ± 2.0 min−1 and had an overall amplitude of 12.3 ± 1.51 mV. We have previously suggested that bursts of STDs may sum to generate the pacemaker potential which propagates to smooth muscle cells to form the depolarising component of the slow wave [1]. Conclusion Slow wave activity can be recorded in the aging guineapig prostate. The configuration of the prostatic slow wave in aging animals is similar to that recorded in younger animals. (1) Lang et al. (2006) Journal of Urology 175(1): p. 370–80.
Introduction and aims doi:10.1016/j.autneu.2007.06.212
The aging male has a risk of developing prostate specific conditions such as benign prostatic hyperplasia, a condition which is typically accompanied by urethral obstruction as a result of an increase in smooth muscle tone. We have previously reported that spontaneous slow wave activity underlies the spontaneous contractions which are likely to contribute to the smooth muscle tone of the prostate. This study aims to characterize the spontaneous slow wave activity in aging guinea pig prostates.
I-P-099 Postnatal downregulation of inhibitory neuromuscular transmission in ileal longitudinal muscle of guinea pigs Xiaochun Bian, Martin Carrasquillo, Joshua E. Burda Department of Pharmacology and Toxicology, Michigan State University; East Lansing, Michigan, USA