scholarly journals Role of spinal α1-adrenoceptor subtypes in the bladder reflex in anesthetized rats

2001 ◽  
Vol 280 (5) ◽  
pp. R1414-R1419 ◽  
Author(s):  
Mitsuharu Yoshiyama ◽  
William C. De Groat
Keyword(s):  
Spinal Cord ◽  
Afferent Input ◽  
Bladder Pressure ◽  
Contraction Amplitude ◽  
Lumbosacral Spinal Cord ◽  
Anesthetized Rats ◽  
Bladder Contraction ◽  
Transurethral Catheter ◽  
Bladder Activity

The contribution of different subtypes of α1-adrenoceptors in the lumbosacral spinal cord to the control of the urinary bladder was examined in urethane-anesthetized rats. Bladder pressure was recorded via a transurethral catheter under isovolumetric conditions. Drugs were administered intrathecally at the L6-S1segmental level of spinal cord. RS-100329 (an α1A-antagonist) in doses of 25, 50, and 100 nmol significantly decreased bladder-contraction amplitude by 38%, 52%, and 95%, respectively, whereas (+)-cyclazosin (an α1B-antagonist) significantly decreased bladder-contraction amplitude (48% reduction) only in a 50-nmol but not a 100-nmol dose. Fifty nanomoles of RS-100329 and (+)-cyclazosin increased bladder-contraction frequency by 54% and 44%, respectively. BMY7378 (an α1D-antagonist), in doses of 25, 50, and 100 nmol, did not change bladder activity. These studies suggest that reflex-bladder activity is modulated by two types of spinal α1-adrenergic mechanisms: 1) α1A- or α1B-inhibitory control of the frequency of voiding reflexes presumably mediated by an alteration in the processing of bladder afferent input and 2) α1A-facilitatory modulation of the descending efferent limb of the micturition-reflex pathway. Spinal α1D-adrenoceptors do not appear to have a significant role at either site.

scholarly journals Spinal proerectile effect of oxytocin in anesthetized rats

2001 ◽  
Vol 280 (6) ◽  
pp. R1870-R1877 ◽  
Author(s):  
François Giuliano ◽  
Jacques Bernabé ◽  
Kevin McKenna ◽  
Florence Longueville ◽  
Olivier Rampin
Keyword(s):  
Spinal Cord ◽  
Penile Erection ◽  
Male Rats ◽  
Lumbosacral Spinal Cord ◽  
Anesthetized Rats ◽  
The Neural Network ◽  
Spinal Cord Level ◽  
Relevant Context ◽  
Descending Projections ◽  
Dose Dependent

The spinal cord contains the neural network that controls penile erection. This network is activated by information from peripheral and supraspinal origin. We tested the hypothesis that oxytocin (OT), released at the lumbosacral spinal cord level by descending projections from the paraventricular nucleus, regulated penile erection. In anesthetized male rats, blood pressure and intracavernous pressure (ICP) were monitored. Intrathecal (it) injection of cumulative doses of OT and the selective OT agonist [Thr4,Gly7]OT at the lumbosacral level elicited ICP rises whose number, amplitude, and area were dose dependent. Thirty nanograms of OT and one-hundred nanograms of the agonist displayed the greatest proerectile effects. Single injections of OT also elicited ICP rises. Preliminary injection of a specific OT-receptor antagonist, hexamethonium, or bilateral pelvic nerve section impaired the effects of OT injected it. NaCl and vasopressin injected it at the lumbosacral level and OT injected it at the thoracolumbar level or intravenously had no effect on ICP. The results demonstrate that OT, acting at the lumbosacral spinal cord, elicits ICP rises in anesthetized rats. They suggest that OT, released on physiological activation of the PVN in a sexually relevant context, is a potent activator of spinal proerectile neurons.

Role of supraspinal and spinal α1-adrenergic receptor subtypes in micturition reflex in conscious rats

2010 ◽  
Vol 299 (4) ◽  
pp. F785-F791 ◽  
Author(s):  
Masaru Yoshizumi ◽  
Kazumasa Matsumoto-Miyai ◽  
Akihiko Yonezawa ◽  
Masahito Kawatani
Keyword(s):  
Spinal Cord ◽  
Receptor Antagonist ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Intrathecal Injection ◽  
Receptor Subtypes ◽  
Lumbosacral Spinal Cord ◽  
Micturition Reflex ◽  
Conscious Rats

α1-Adrenergic receptor subtypes are widely distributed in the central nervous system and are involved in autonomic functions such as micturition. We investigated the presence and the role of supraspinal and/or spinal α1-adrenergic receptors in modulating the micturition reflex in conscious female Wistar rats. The expression of α1-adrenergic receptor subtypes in rat brain and lumbosacral spinal cord was studied using RT-PCR. Continuous-infusion cystometrograms were obtained in conscious rats, and α1-adrenergic receptor antagonists were administered via intracerebroventricular or intrathecal routes. The mRNA expression of α1A-, α1B-, and α1D-adrenergic receptors was detected in rat brain (midbrain and pons) and lumbosacral spinal cord (dorsal and ventral parts of spinal cord). In addition, intracerebroventricular injection of the α1-adrenergic receptor antagonist tamsulosin (1–10 μg), the selective α1A-adrenergic receptor antagonist silodosin (1–10 μg), and the selective α1D-adrenergic receptor antagonist BMY 7378 (1–10 μg) significantly prolonged the intercontraction interval (ICI) but did not alter maximum voiding pressure (MVP). Although intrathecal injection of BMY 7378 (0.0001–10 μg) did not affect ICI, tamsulosin and silodosin prolonged ICI in a dose-dependent manner. MVP was significantly reduced by intrathecal injection of tamsulosin (10 μg) but not by silodosin or BMY 7378 (0.0001–10 μg). Supraspinal α1A- and α1D-adrenergic receptors are apparently important for the regulation of reflex-bladder activity in conscious rats. Noradrenergic projection from the brain stem to the lumbosacral spinal cord may promote the afferent limb rather than the efferent limb of the micturition reflex pathway via α1A-adrenergic receptors.

Spinal Micturition Reflex Mediated by Afferents in the Deep Perineal Nerve

2005 ◽  
Vol 93 (5) ◽  
pp. 2688-2697 ◽  
Author(s):  
Joseph W. Boggs ◽  
Brian J. Wenzel ◽  
Kenneth J. Gustafson ◽  
Warren M. Grill
Keyword(s):  
Spinal Cord ◽  
Bladder Pressure ◽  
Detrusor Muscle ◽  
Urethral Sphincter ◽  
Lumbosacral Spinal Cord ◽  
Sensory Pathways ◽  
Tension Properties ◽  
Before And After ◽  
Spinal Circuit ◽  
40 Hz

Reflexes mediated by urethral sensory pathways are integral to urinary function. This study investigated the changes in bladder pressure and urethral sphincter activity resulting from electrical stimulation of afferents in the deep perineal nerve (DP), which innervates the urethra and surrounding muscles, before and after acute spinal cord transection (SCT) in cats anesthetized with α-chloralose monitored by blood pressure and heart rate. DP stimulation elicited bladder contractions before and after SCT but only if the bladder contained a sufficient volume of fluid (78% of the volume needed to cause distention-evoked reflex contractions). The volume dependency was mediated by a neuronal mechanism in the lumbosacral spinal cord and was not attributable to length-tension properties of the detrusor muscle. Stimulation at 2–40 Hz initiated bladder contractions, but 20–40 Hz was more effective than lower frequencies in evoking and sustaining bladder contractions for the duration of the stimulus train. Decreases in urethral sphincter activity occurred during sustained bladder contractions evoked by 20- to 40-Hz stimulation before and within 16 h after SCT. After SCT, average bladder pressure increases evoked by DP stimulation were smaller than those evoked before SCT, but in some animals, bladder pressures elicited by DP stimulation continued to increase as time after SCT increased and reached pretransection amplitudes at 8–16 h posttransection. These data confirm the presence of a spinal circuit that can mediate coordinated bladder–sphincter responses and show that afferents from the DP can activate this circuit under appropriate conditions.

Role of Aδ afferent fibers in modulation of primary afferent input to the adult rat spinal cord

1995 ◽  
Vol 691 (1-2) ◽  
pp. 92-98 ◽  
Author(s):  
T. Shimizu ◽  
M. Yoshimura ◽  
H. Baba ◽  
K. Shimoji ◽  
H. Higashi
Keyword(s):  
Spinal Cord ◽  
Afferent Input ◽  
Rat Spinal Cord ◽  
Primary Afferent ◽  
Adult Rat ◽  
Afferent Fibers ◽  
Adult Rat Spinal Cord

scholarly journals Role of the endogenous opioid system in modulation of urinary bladder activity by spinal nerve stimulation

2013 ◽  
Vol 305 (1) ◽  
pp. F52-F60 ◽  
Author(s):  
Xin Su ◽  
Angela Nickles ◽  
Dwight E. Nelson
Keyword(s):  
Urinary Bladder ◽  
Spinal Nerve ◽  
Opioid Antagonist ◽  
Inhibitory Effects ◽  
Endogenous Opioid System ◽  
Endogenous Opioid ◽  
Contraction Frequency ◽  
Bladder Contraction ◽  
Bladder Activity

The role of the endogenous opioid system in modulation of urinary bladder activity by spinal nerve (SN) stimulation was studied in anesthetized female rats, using the rat model of isovolumetric bladder contraction. SN stimulation at a fixed frequency of 10 Hz attenuated bladder contraction frequency; the magnitude of the inhibition was directly proportional to the current intensity. Neither the κ-opioid antagonist nor-binaltorphimine (2 mg/kg iv) nor the δ-opioid antagonist naltrindole (5 mg/kg iv) attenuated the bladder inhibitory response to SN stimulation. In contrast, the μ-opioid receptor antagonist naloxone (NLX; 0.03 mg/kg iv) blocked the inhibitory responses evoked by SN stimulation at therapeutic current intensities at ≤1 × motor threshold current (Tmot). An action at spinal and supraspinal centers was further confirmed by the ability of intrathecal or intracerebroventricular administration of NLX methiodide to attenuate the bladder inhibitory effects of 1 × Tmot SN stimulation. The magnitude of SN-mediated neuromodulation using therapeutically relevant stimulation intensity (Tmot) is equivalent to 0.16 mg/kg of systemically administered morphine, which produces 50% inhibition of bladder contraction frequency. These results suggest that the inhibitory effects of lower intensity SN stimulation may be mediated through the release of endogenous μ-opioid peptides. Additionally, these data suggest that neuromodulation may offer a mode of treating the symptoms of overactive bladder with efficacy equal to the opioid drugs but without their liability for abuse and dependence.

A critical period for the specification of motor pools in the chick lumbosacral spinal cord

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 659-669 ◽  
Author(s):  
M.P. Matise ◽  
C. Lance-Jones
Keyword(s):  
Spinal Cord ◽  
Neural Tube ◽  
Regional Differences ◽  
Critical Period ◽  
Local Environment ◽  
Lumbosacral Spinal Cord ◽  
Motor Columns ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

When 3–4 segments of the chick lumbosacral neural tube are reversed in the anterior-posterior axis at stage 15 (embryonic day 2.5), the spinal cord develops with a reversed organization of motoneurons projecting to individual muscles in the limb (C. Lance-Jones and L. Landmesser (1980) J. Physiol. 302, 581–602). This finding indicated that motoneuron precursors or components of their local environment were specified with respect to target by stage 15. To identify the timing of this event, we have now assessed motoneuron projections after equivalent neural tube reversals at earlier stages of development. Lumbosacral neural tube segments 1–3 (+/− one segment cranial or caudal) were reversed in the anterior-posterior axis at stages 13 and 14 (embryonic day 2). The locations of motoneurons innervating two thigh muscles, the sartorius and femorotibialis, were mapped via retrograde horseradish peroxidase labeling at stages 35–36 (embryonic days 9–10). In a sample of embryos, counts were made of the total number of motoneurons in the lateral motor columns of reversed segments. The majority of motoneurons projecting to the sartorius and femorotibialis were in a normal position within the spinal cord. Segmental differences in motor column size were also similar to normal. These observations indicate that positional cues external to the LS neural tube can affect motoneuron commitment and number at stages 13–14. Since these observations stand in contrast to results following stage 15 reversals, we conclude that regional differences related to motoneuron target identity are normally specified or stabilized within the anterior LS neural tube between stages 14 and 15. To examine the role of the notochord in this process, neural tube reversals were performed at stages 13–14 as described above, except that the underlying notochord was also reversed. Projections to the sartorius and femorotibialis muscles did not differ significantly from those in embryos with neural tube reversals alone, indicating that the notochord is not the source of cues for target identity at stages 13–14.

Ovarian blood flow responses to electroacupuncture stimulation depend on estrous cycle and on site and frequency of stimulation in anesthetized rats

2006 ◽  
Vol 101 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Elisabet Stener-Victorin ◽  
Shigeko Fujisawa ◽  
Mieko Kurosawa
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Estrous Cycle ◽  
Sympathetic Nerves ◽  
Spinal Cord Transection ◽  
Reflex Response ◽  
Hindlimb Muscles ◽  
Anesthetized Rats ◽  
Frequency Of Stimulation

Electroacupuncture (EA) applied to the abdomen and hindlimb modulates the ovarian blood flow (OBF) response. The present study aimed to further elucidate the role of the site and the frequency of short-term EA stimulation and the influence of the estrous cycle on the OBF response using anesthetized rats. EA stimulation was applied to the abdominal or the hindlimb muscles at three different frequencies (2, 10, and 80 Hz) during the estrus or diestrus phase. Involvement of spinal and supraspinal reflexes in OBF responses to EA stimulation was investigated by spinal cord transection. Abdominal EA stimulation at 10 Hz increased the OBF response, whereas hindlimb EA stimulation at 10 Hz and abdominal and hindlimb stimulation at 80 Hz decreased the OBF response; 2-Hz EA caused no OBF response. The OBF response to abdominal EA was more pronounced in the estrus than the diestrus phase. The OBF response to abdominal and hindlimb EA stimulation at both 10 and 80 Hz was almost abolished, both after severance of the sympathetic nerves and after spinal cord transection. In conclusion, the OBF response to both abdominal and hindlimb EA stimulation was mediated as a reflex response via the ovarian sympathetic nerves, and the response was controlled via supraspinal pathways. Furthermore, the OBF response to segmental abdominal EA stimulation was frequency dependent and amplified in the estrous phase.

scholarly journals Role of spinal metabotropic glutamate receptor 5 in pudendal inhibition of the nociceptive bladder reflex in cats

2015 ◽  
Vol 308 (8) ◽  
pp. F832-F838 ◽  
Author(s):  
Jeremy N. Reese ◽  
Marc J. Rogers ◽  
Zhiying Xiao ◽  
Bing Shen ◽  
Jicheng Wang ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
Bladder Capacity ◽  
Spinal Reflex ◽  
Saline Control ◽  
Metabotropic Glutamate Receptor 5 ◽  
Contraction Amplitude ◽  
Metabotropic Glutamate ◽  
Bladder Contraction ◽  
C Fiber

This study examined the role of spinal metabotropic glutamate receptor 5 (mGluR5) in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in the inhibtion of this reflex by pudendal nerve stimulation (PNS). In α-chloralose-anesthetized cats after spinal cord transection at the T9/T10 level, intravesical infusion of 0.25% acetic acid irritated the bladder, activated nociceptive C-fiber afferents, and induced spinal reflex bladder contractions of low amplitude (<50 cmH2O) and short duration (<20 s) at a smaller bladder capacity ∼80% of saline control capacity. PNS significantly ( P < 0.01) increased bladder capacity from 85.5 ± 10.1 to 137.3 ± 14.1 or 148.2 ± 11.2% at 2T or 4T stimulation, respectively, where T is the threshold intensity for PNS to induce anal twitch. MTEP {3-[(2-methyl-4-thiazolyl)ethynyl]pyridine; 3 mg/kg iv, a selective mGluR5 antagonist} completely removed the PNS inhibition and significantly ( P < 0.05) increased bladder capacity from 71.8 ± 9.9 to 94.0 ± 13.9% of saline control, but it did not change the bladder contraction amplitude. After propranolol (3 mg/kg iv, a β1/β2-adrenergic receptor antagonist) treatment, PNS inhibition remained but MTEP significantly ( P < 0.05) reduced the bladder contraction amplitude from 18.6 ± 2.1 to 6.6 ± 1.2 cmH2O and eliminated PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly ( P < 0.05) reduced the bladder contraction amplitude from 20.9 ± 3.2 to 8.1 ± 1.5 cmH2O on average demonstrating that spinal reflexes were responsible for a major component of the contractions. This study shows that spinal mGluR5 plays an important role in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in pudendal inhibition of this spinal reflex.

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