Mid-lumbar (L3) epidural stimulation effects on bladder and external urethral sphincter in non-injured and chronically transected urethane-anesthetized rats.

Recent pre-clinical and clinical spinal cord epidural stimulation (scES) experiments specifically targeting the thoracolumbar and lumbosacral circuitries mediating lower urinary tract (LUT) function have shown improvements in storage, detrusor pressure, and emptying. With the existence of a lumbar spinal coordinating center in rats that is involved with external urethral sphincter (EUS) functionality during micturition, the mid-lumbar spinal cord (specifically L3) was targeted in the current study with scES to determine if the EUS and thus the void pattern could be modulated, using both intact and chronic complete spinal cord injured female rats under urethane anesthesia. L3 scES at select frequencies and intensities of stimulation produced a reduction in void volumes and EUS burst duration in intact rats. After chronic transection, three different subgroups of LUT dysfunction were identified and the response to L3 scES promoted different cystometry outcomes, including changes in EUS bursting. The current findings suggest that scES at the L3 level can generate functional neuromodulation of both the urinary bladder and the EUS in intact and SCI rats to enhance voiding in a variety of clinical scenarios.

Thoracolumbar epidural stimulation effects on bladder and bowel function in uninjured and chronic transected anesthetized rats.

Pre-clinical studies have shown that spinal cord epidural stimulation (scES) at the level of pelvic and pudendal nerve inputs/outputs (L5-S1) alters storage and/or emptying functions of both the bladder and bowel. The current mapping experiments were conducted to investigate scES efficacy at the level of hypogastric nerve inputs/outputs (T13-L2) in male and female rats under urethane anesthesia. As found with L5-S1 scES, T13-L2 scES at select frequencies and intensities of stimulation produced an increase in inter-contraction interval (ICI) in non-injured female rats but a short-latency void in chronic T9 transected rats, as well as reduced rectal activity in all groups. However, the detrusor pressure during the lengthened ICI (i.e., urinary hold) remained at a low pressure and was not elevated as seen with L5-S1 scES, an effect that's critical for translation to the clinic as high fill pressures can damage the kidneys. Furthermore, T13-L2 scES was shown to stimulate voiding post-transection by increasing bladder activity while also directly inhibiting the external urethral sphincter, a pattern necessary to overcome detrusor-sphincter dyssynergia. Additionally, select scES parameters at T13-L2 also increased distal colon activity in all groups. Together, the current findings suggest that optimization of scES for bladder and bowel will likely require multiple electrode cohorts at different locations that target circuitries coordinating sympathetic, parasympathetic and somatic outputs.

Bladder and bowel responses to lumbosacral epidural stimulation in uninjured and transected anesthetized rats.

Spinal cord epidural stimulation (scES) mapping at L5-S1 was performed to identify parameters for bladder and bowel inhibition and/or contraction. Using spinally intact and chronic transected rats of both sexes in acute urethane-anesthetized terminal preparations, scES was systematically applied using a modified Specify 5-6-5 (Medtronic) electrode during bladder filling/emptying cycles while recording bladder and colorectal pressures and external urethral and anal sphincter electromyography activity. The results indicate frequency-dependent effects on void volume, micturition, bowel peristalsis, and sphincter activity just above visualized movement threshold intensities that differed depending upon neurological intactness, with some sex-dependent differences. Thereafter, a custom-designed miniature 15-electrode array designed for greater selectivity was tested and exhibited the same frequency-dependent urinary effects over a much smaller surface area without any concurrent movements. Thus, select activation of autonomic nervous system circuitries with scES is a promising neuromodulation approach for expedient translation to individuals with SCI and potentially other neurologic disorders.

Choice of cystometric technique impacts detrusor contractile dynamics in wistar rats.

The objective of the current animal study was to investigate factors contributing to the different phases of the cystometrogram (CMG) in order to address disparities in research data reported in the current literature. Three experiments in 20 female Wistar rats were designed to investigate (1) the effects of anesthesia on the contractile pattern of the bladder during micturition; (2) the impact of the physical characteristics of the CMG technique upon the accuracy of intra-vesical pressure recordings; and (3) identification of physiological and methodological factors associated with the emptying and rebound phases during CMG. Variables tested included awake versus urethane-anesthetized conditions, use of a single catheter for both filling and intra-vesical pressure (Pves) recording versus a separate two catheter approach, and comparisons between ureter, bladder dome, and urethral catheter placements. Both awake and anesthetized conditions contributed to variations in the shape and magnitude of the CMG pressure curves. In addition, catheter size, acute incision of the bladder dome for catheter placement, use of the same catheter for filling and Pves recordings, as well as the placement and positioning of the tubing, all contributed to alterations of the physiological properties and characteristic of the various CMG phases, including the frequent occurrence of an artificial rebound during the third phase of micturition. The present results demonstrate how different experimental conditions lead not only to variability in Pves curves, but consistency of the measurements as well, which needs to be accounted for when interpreting CMG outcome data.

Investigation of Bowel Function with Anorectal Manometry in a Rat Spinal Cord Contusion Model.

Bowel dysfunction after chronic spinal cord injury (SCI) is a common source of morbidity and rehospitalization. Typical complications include constipation, fecal impaction, incontinence, abdominal distention, autonomic dysreflexia, and the necessity of interventions (i.e., suppositories, digital stimulation) to defecate. Numerous surveys have confirmed that the remediation of bowel complications is more highly valued for quality of life than improvements in walking. Much of what is known about bowel function after SCI for diagnosis and research in humans has been gained using anorectal manometry (ARM) procedures. However, ARM has been underutilized in pre-clinical animal work. Therefore, a novel combination of outcome measures was examined in the current study that incorporates functional output of the bowel (weekly fecal measurements), weight gain (pre-injury to terminal weight), and terminal ARM measurement with external anal sphincter electromyography under urethane anesthesia. The results indicate higher fecal output after contusion during the sub-acute period (4-7 days) post-injury, changes in the composition of the feces, and functionally obstructive responses in a specific section of the rectum (increased baseline pressure, increased frequency of contraction, and reduced ability to trigger a giant contraction to a distension stimulus). These results demonstrate significant bowel dysfunction in the rodent SCI contusion model that is consistent with data from human research. Thus, the combined measurement protocol enables the detection of changes and can be used, with minimal cost, to assess effectiveness of therapeutic interventions on bowel complications.

Activity-Based Training Alters Penile Reflex Responses in a Rat Model of Spinal Cord Injury.

INTRODUCTION: Multisystem functional gains have been reported in males with spinal cord injury (SCI) after undergoing activity-based training (ABT), including increases in scoring of sexual function and reports of improved erectile function. AIM: This study aims to examine the effect of daily 60-minute locomotor training and exercise in general on sexual function in a rat SCI contusion model. METHODS: Male Wistar rats received a T9 contusion SCI. Animals were randomized into 4 groups: a quadrupedal stepping group (SCI + QT), a forelimb-only exercise group (SCI + FT), a non-trained harnessed group (SCI + NT), and a home cage non-trained group (SCI + HC). The 2 non-trained groups were combined (SCI) post hoc. Daily training sessions were 60 minutes in duration for 8 weeks. Urine samples were collected during bi-weekly 24-hour metabolic cage behavioral testing. Latency, numbers of penile dorsiflexion, and glans cupping were recorded during bi-weekly penile dorsiflexion reflex (PDFR) testing. Terminal electromyography (EMG) recordings of the bulbospongiosus muscle (BSM) were recorded in response to stimulation of the dorsal nerve of the penis (DNP). OUTCOMES: ABT after SCI had a significant effect on PDFR, as well as BSM EMG latency and burst duration. RESULTS: SCI causes a significant decrease in the latency to onset of PDFR. After 8 weeks of ABT, SCI + QT animals had a significantly increased latency relative to the post-SCI baseline. BSM EMG response to DNP stimulation had a significantly decreased latency and increase in average and maximum amplitude in SCI + QT animals. SCI animals had a significantly longer burst duration than trained animals. Time between PDFR events, penile dorsiflexion, glans cupping, and urine testosterone were not affected by ABT. CLINICAL IMPLICATIONS: ABT has a positive influence on sexual function and provides a potential therapy to enhance the efficacy of current sexual dysfunction therapies in the male SCI population. STRENGTHS AND LIMITATIONS: Several significant small improvements in sexual function were found in a clinically relevant rat model of SCI using a readily available rehabilitative therapy. The limited findings could reflect insensitivity of the PDFR as a measure of erectile function. CONCLUSIONS: These results indicate that task-specific stepping and/or loading provide sensory input to the spinal cord impacting the neural circuitry responsible for sexual function. Steadman CJ, Hoey RF, Montgomery LR, et al. Activity-Based Training Alters Penile Reflex Responses in a Rat Model of Spinal Cord Injury. J Sex Med 2019; 16:1143-1154.

Activity-based Training on a Treadmill with Spinal Cord Injured Wistar Rats.

Spinal cord injury (SCI) results in lasting deficits that include both mobility and a multitude of autonomic-related dysfunctions. Locomotor training (LT) on a treadmill is widely used as a rehabilitation tool in the SCI population with many benefits and improvements to daily life. We utilize this method of activity-based task-specific training (ABT) in rodents after SCI to both elucidate the mechanisms behind such improvements and to enhance and improve upon existing clinical rehabilitation protocols. Our current goal is to determine the mechanisms underlying ABT-induced improvements in urinary, bowel, and sexual function in SCI rats after a moderate to severe level of contusion. After securing each individual animal in a custom-made adjustable vest, they are secured to a versatile body weight support mechanism, lowered to a modified three-lane treadmill and assisted in step-training for 58 minutes, once a day for 10 weeks. This setup allows for the training of both quadrupedal and forelimb-only animals, alongside two different non-trained groups. Quadrupedal-trained animals with body weight support are aided by a technician present to assist in stepping with proper hind limb placement as necessary, while forelimb-only trained animals are raised at the caudal end to ensure no hind limb contact with the treadmill and no weight-bearing. One non-trained SCI group of animals is placed in a harness and rests next to the treadmill, while the other control SCI group remains in its home cage in the training room nearby. This paradigm allows for the training of multiple SCI animals at once, thus making it more time-efficient in addition to ensuring that our pre-clinical animal model mimics the clinical representation as close as possible, particularly with respect to the body weight support with manual assistance.

Parenting and concerns of pregnant women in buprenorphine treatment.

PURPOSE: Opioid-dependent pregnant women are characterized by drug use during pregnancy and deficits in knowledge of newborn care and feeding, and of child development. We assessed parenting skills and concerns among pregnant women in buprenorphine treatment for prescription opioid dependence. STUDY DESIGN AND METHODS: We interviewed 32 pregnant women who received buprenorphine treatment for prescription opioid dependence in a primary care setting and administered questionnaires, including the Adult-Adolescent Parenting Inventory version 2 (AAPI-2) and Childhood Experience of Care and Abuse Questionnaire. RESULTS: AAPI-2 scores revealed medium risk of abuse for all five scales: inappropriate expectations of the child, low level of empathy, strong belief in corporal punishment, reversal of parent-child roles, and oppression of children's power and independence. Primary concerns of participants were neonatal abstinence syndrome (NAS) and their child's health. Pregnant women who received buprenorphine for treatment of prescription opioid dependence showed a lack of appropriate parenting skills, but did not express concern about their ability to parent. CLINICAL IMPLICATIONS: Our findings suggest a need for nurses to assist prescription opioid-dependent pregnant women in acquiring additional parenting skills, to refer for educational parenting intervention, and to educate patients about NAS.

Effect of amniotic-fluid ingestion on vaginal-cervical-stimulation-induced Fos expression in female rats during estrus.

Placental Opioid-Enhancing Factor (POEF) is a substance found in amniotic fluid (AF) that, when ingested, potentiates opioid-mediated, but not non-opioid-mediated, hypoalgesia. Vaginal-cervical stimulation (VCS) produces a stimulus-bound, partially opioid-mediated hypoalgesia that previous research has shown to be potentiated by AF ingestion. To understand the mechanism of opioid enhancement by POEF we investigated the pattern of neural activation after a bout of VCS that produced hypoalgesia, with and without co-administration of AF. Specifically, virgin Long-Evans rats showing vaginal estrus were handled briefly (control) or received VCS (75g pressure, 1 min), in a pattern that approximated early parturition rather than copulation, using a spring-loaded glass-rod probe. Rats were given an orogastric infusion (0.25 ml) of either AF or 0.9% saline resulting in four groups (VCS or handling; AF or saline). Rats were perfused 90 min after treatment and tissue was processed by immunohistochemistry for Fos. The number of Fos-immunoreactive cells was counted in structures previously shown to express Fos in response to VCS (the medial preoptic area, MPOA; the ventrolateral portion of the ventromedial hypothalamic nucleus, vlVMH; the arcuate nucleus, ARC). We found that this pattern of VCS did not produce a significant increase in Fos expression in the MPOA and vlVMH unless it was paired with AF. VCS produced a significant increase in Fos in the ARC. The interaction of AF and VCS on Fos expression in the MPOA suggests that POEF may enhance vaginal-cervical sensory input at parturition to facilitate sensitization of the MPOA, and presumably facilitate maternal-behavior onset.

Ingestion of amniotic fluid enhances the facilitative effect of VTA morphine on the onset of maternal behavior in virgin rats.

Previous research has shown that injection of morphine into the ventral tegmental area (VTA) facilitates the onset of maternal behavior in virgin female rats, and injection of the opioid antagonist naltrexone into the VTA disrupts the onset of maternal behavior in parturient rats. Placentophagia -- ingestion of placenta and amniotic fluid, usually at parturition -- modifies central opioid processes. Ingestion of the active substance in placenta and amniotic fluid, Placental Opioid-Enhancing Factor (POEF), enhances the hypoalgesic effect of centrally administered morphine, and more specifically, enhances delta- and kappa-opioid-receptor-mediated hypoalgesia and attenuates mu-opioid-receptor-mediated hypoalgesia. POEF (in placenta or amniotic fluid) ingestion does not, by itself, produce hypoalgesia. In the present study, we tested the hypothesis that ingestion of amniotic fluid enhances the facilitative effect of opioid activity (unilateral morphine injection) in the VTA on the rate of onset of maternal behavior. Virgin female Long-Evans rats were given one intra-VTA injection of morphine sulfate (0.0, 0.01, or 0.03 microg, in saline) and an orogastric infusion of 0.25 ml amniotic fluid or saline once each day of the first three days of the 10-day testing period. Subjects were continuously exposed to foster pups that were replaced every 12 h; replacement of pups was followed by a 15-min observation period. Maternal behavior latency was determined by the first of two consecutive tests wherein the subject displayed pup retrieval, pup licking in the nest, and crouching over all foster pups, during the 15-min observation. We confirmed the previous finding that the VTA injection, alone, of 0.03 microg morphine shortened the latency to show maternal behavior and that 0.0 microg and 0.01 microg morphine did not. Ingestion of amniotic fluid (and therefore POEF) facilitated the onset of maternal behavior in rats receiving an intra-VTA microinjection of an otherwise subthreshold dose of morphine (0.01 microg).