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Immunoreactive Arginine Vasopressin in Human Penile Erectile Tissues
Prosthesis/ Sexual Function 1090
1091
HYDROFLEX PENILE PROSTHESIS: COMMENTS AND RECOMMENDATIONS
ELECTROPHYSIOLOGICAL ANALYSIS OF PENILE REFLEXES IN THE RAT Steers, W.D.*, Mallory, B*., de Groat, W.C. * Pittsburgh, PA (Presentation by Dr. Steers). Reflex pathways to the penis are poorly defined. The rat offers a simple model for studying such pathways and their interactions at the level of the pelvic plexus since a single major pelvic ganglion is present. Male Wistar rats (250-350 g) anesthetized with urethane (1.2 g/kg s.c.) underwent microsurgical exposure of the hypogastric (HGN), pelvic (PV), postganglionic nerves to the bladder (PgBl) and penis (PgP), and dorsal nerve of the penis (DNP)for stimulation and recording. Stimulation of the DNP resulted in short latency (8-17 ms) responses on the PgP (13 ± 4ms), PgBl (13±2 ms),PV (11± 3ms), and HGN (11± 3ms) nerves. Lon~ latency (40-BOms) reflexes were recorded on the PgP (52-lOmsl, HGN, and PV nerves. Both short and long latency responses were abolished by hexamethonium (40mg/kg), and increased frequencies (2-7Hz) stimulation indicating that these responses were synaptic in nature. PV transection also eliminated these short and long latency responses while sectioning the HGN proxi~ally or the PgP distally did not alter these respo~ses. Thoracic cord transection did not abolish short or 1ong latency responses. These electrophysiological results support the role of DNP as the afferent component of the penile erectile mechanism which is mediated by a polysynaptic lumbosacral spinal pathway. This afferent component does not appear to travel in the PgP. Efferent pathways project to the penis via the PV. Numerous short latency local reflexes, such as penis to bladder reflexes, are present whose physiological significance is uncertain. These results indicate a similar organization of neural pathways to the penis in the rat and man and therefore demonstrate that the rat is a useful model for studying the neural control of sexual function.
H. David Mitcheson* and Edwin M. Meares, Jr., Boston.
15 patients with organic impotence have been implanted with the Hydroflex (HFX) penile prosthesis since it became available 1 year ago. Follow-up is necessarily short but useful comments can already be made. Patients and partners completed questionaires before implantation and 2 and 12 weeks later. The length and width of the penis was measured flaccid, after erectorset tumescence and after implantation
with the HFX inflated and deflated. The HFX is available in 6 standard sizes with rear tip extenders. 9 patients were fitted without rear tip extenders, 5 required extenders. Penile width on erectorset was used to select the HFX diameter. The HFX inflation measurements when compared to erectorset were excellent as were tumescence measurements. Deflation characteristics were good except in 1. His fluid pass8geway was placed ventrally as. recommended but this
kinkedblocking deflation. Placing the fluid passageway dorsally obviates this problem. There was no relationship between crural length and deflation characteristics. Patients
with short penis and short crural length had problems with the rear mechanism protruding into the shaft if extenders were used. Since the HFX can not be resterilized it is imperative to measure accurately. The best method is to use the Jonas sizer to measure then use resterilizable Flexirods to determine the exact fit. Most patients were comfortable after 2 weeks and learned to use the device in 2 sessions.
Apart from the deflation difficulty there were no early mechanical failures. 12 patients considered the device excellent, 1 good and 1 terrible. Partner satisfaction was equal-
ly satisfactory. 4 patients had spinal injuries. For them the deflated HFX was soft with minimal risk for erosion yet provided much improved condom retention. Quadraplegic patients had the device operated by their partners. We conclude our early experience with the HFX penile prosthesis has been most satisfactory. Practical tips are given and the manufacturer is requested to provide more standard sizes.
1092
1093
IMMUNDREACTIVE ARGININE VASDPRESSIN IN HUMAN PENILE ERECTILE TISSUES. Hans Hedlundf Karl-Erik Anderssonf Magnus Fovaeus*and Stefan Lundint Lund, Sweden (Presentation to be made by Dr Hans Hedlund). Arginine vasopressin (AVP) has been found in human testicular tissue in concentrations too great to be explained by known circulating levels of the hormone. In human penile erectile muscles AVP has not been demonstrated, but it is known that the peptide in low concentrations has a contractile effect on these muscles. As it cannot be excluded that AVP is involved in the mechanisms 6f penile erection, the present study was performed to determine the concentrations of AVP in human penile smooth muscles, and explore the possibility that is has a functional role in these tissues. Specimens of corpus spongiosum (CS) and corpus cavernosum (CC) were obtained from 20 men, aged 59-75 years, who underwent cystourethrectomy because of bladder cancer. They had all a history of normal penile erection. AVP was determined by radioimmunoassay, and extracted immunoreactive (IR) material was characterized by means of high performance liquid chromatography. In experiments on isolated CS tissue, four AVP antagonists were characterized and their effects on electrically induced contractions in CS and CC strips were investigated. IR-AVP was found in CS and CC in amounts considerably higher than those found in circulating blood, suggesting that AVP is stored and/or synthetized locally. The AVP antagonists tested reduced contractions induced by AVP in CS and CC strips, but did not affect electrically induced contractions in these tissues. The results suggest that even if human penile erectile smooth muscles contain AVP, the peptide seems not to be released on electrical stimulation and consequently serves not as a contractile transmitter in these tissues.
EFFECT OF SPINAL ANESTHESIA ON ERECTION IN THE MONKEY. *Stefan C. Muller, *Mark R. Fahey, San Francisco, CA (Presentation to be made by Dr. M..tller) Five "chronic" rronkeys having electrodes :inplanted around the caven10us nerve for electro-erection were studied before and after spinal anesthesia at the level of L3/L4 (10-30 rrg Lidocaine 1.5% with Dextrose 7 .5%). Prior to spinal anesthesia, all rronkeys were sedated with Ketamine (10-15 rrg/kg im.) and intracavernous pressures were rreasured through a 21-gauge butterfly needle =nnected to a Statham transducer. Arterial blocxl pressures were repeatedly rronitored using a pediatric blocxl pressure cuff and a Doppler probe on the radial artery. Intracavernous pressure changes of electro-erection were recorded repeatedly before and after spinal anesthesia. The effect and level of spinal anesthesia was docurrented by paralyzed legs during light Ketamine sedation. After injection of Lidocaine, and with the IlDnkeys in supine position, the penis showed turrescence and elongation with very little pressure increase. Stimulation of the cavernous nerve showed the erectile response (intracavernous pressure) in direct relation to the peak systolic blocxl pressure. When stinulation was tenninated, the erection was markedly prolonged. In one nonkey, the intracavernous pressure went high above the systolic blocxl pressure, although a slight penile retraction could be observed. Obviously, there was an imbalance in the neurophysiology between turrescence and deturrescence factors. We assurre that blockade of the sympathetic nerve system caused prolonged erection, and that the unaffected intrinsic tone of the cavernous SllOOth muscle was responsible for the slight penile retraction, but increasing intracavemous pressure while the venous drainage system was caupressed.
376A
1091
HYDROFLEX PENILE PROSTHESIS: COMMENTS AND RECOMMENDATIONS
ELECTROPHYSIOLOGICAL ANALYSIS OF PENILE REFLEXES IN THE RAT Steers, W.D.*, Mallory, B*., de Groat, W.C. * Pittsburgh, PA (Presentation by Dr. Steers). Reflex pathways to the penis are poorly defined. The rat offers a simple model for studying such pathways and their interactions at the level of the pelvic plexus since a single major pelvic ganglion is present. Male Wistar rats (250-350 g) anesthetized with urethane (1.2 g/kg s.c.) underwent microsurgical exposure of the hypogastric (HGN), pelvic (PV), postganglionic nerves to the bladder (PgBl) and penis (PgP), and dorsal nerve of the penis (DNP)for stimulation and recording. Stimulation of the DNP resulted in short latency (8-17 ms) responses on the PgP (13 ± 4ms), PgBl (13±2 ms),PV (11± 3ms), and HGN (11± 3ms) nerves. Lon~ latency (40-BOms) reflexes were recorded on the PgP (52-lOmsl, HGN, and PV nerves. Both short and long latency responses were abolished by hexamethonium (40mg/kg), and increased frequencies (2-7Hz) stimulation indicating that these responses were synaptic in nature. PV transection also eliminated these short and long latency responses while sectioning the HGN proxi~ally or the PgP distally did not alter these respo~ses. Thoracic cord transection did not abolish short or 1ong latency responses. These electrophysiological results support the role of DNP as the afferent component of the penile erectile mechanism which is mediated by a polysynaptic lumbosacral spinal pathway. This afferent component does not appear to travel in the PgP. Efferent pathways project to the penis via the PV. Numerous short latency local reflexes, such as penis to bladder reflexes, are present whose physiological significance is uncertain. These results indicate a similar organization of neural pathways to the penis in the rat and man and therefore demonstrate that the rat is a useful model for studying the neural control of sexual function.
H. David Mitcheson* and Edwin M. Meares, Jr., Boston.
15 patients with organic impotence have been implanted with the Hydroflex (HFX) penile prosthesis since it became available 1 year ago. Follow-up is necessarily short but useful comments can already be made. Patients and partners completed questionaires before implantation and 2 and 12 weeks later. The length and width of the penis was measured flaccid, after erectorset tumescence and after implantation
with the HFX inflated and deflated. The HFX is available in 6 standard sizes with rear tip extenders. 9 patients were fitted without rear tip extenders, 5 required extenders. Penile width on erectorset was used to select the HFX diameter. The HFX inflation measurements when compared to erectorset were excellent as were tumescence measurements. Deflation characteristics were good except in 1. His fluid pass8geway was placed ventrally as. recommended but this
kinkedblocking deflation. Placing the fluid passageway dorsally obviates this problem. There was no relationship between crural length and deflation characteristics. Patients
with short penis and short crural length had problems with the rear mechanism protruding into the shaft if extenders were used. Since the HFX can not be resterilized it is imperative to measure accurately. The best method is to use the Jonas sizer to measure then use resterilizable Flexirods to determine the exact fit. Most patients were comfortable after 2 weeks and learned to use the device in 2 sessions.
Apart from the deflation difficulty there were no early mechanical failures. 12 patients considered the device excellent, 1 good and 1 terrible. Partner satisfaction was equal-
ly satisfactory. 4 patients had spinal injuries. For them the deflated HFX was soft with minimal risk for erosion yet provided much improved condom retention. Quadraplegic patients had the device operated by their partners. We conclude our early experience with the HFX penile prosthesis has been most satisfactory. Practical tips are given and the manufacturer is requested to provide more standard sizes.
1092
1093
IMMUNDREACTIVE ARGININE VASDPRESSIN IN HUMAN PENILE ERECTILE TISSUES. Hans Hedlundf Karl-Erik Anderssonf Magnus Fovaeus*and Stefan Lundint Lund, Sweden (Presentation to be made by Dr Hans Hedlund). Arginine vasopressin (AVP) has been found in human testicular tissue in concentrations too great to be explained by known circulating levels of the hormone. In human penile erectile muscles AVP has not been demonstrated, but it is known that the peptide in low concentrations has a contractile effect on these muscles. As it cannot be excluded that AVP is involved in the mechanisms 6f penile erection, the present study was performed to determine the concentrations of AVP in human penile smooth muscles, and explore the possibility that is has a functional role in these tissues. Specimens of corpus spongiosum (CS) and corpus cavernosum (CC) were obtained from 20 men, aged 59-75 years, who underwent cystourethrectomy because of bladder cancer. They had all a history of normal penile erection. AVP was determined by radioimmunoassay, and extracted immunoreactive (IR) material was characterized by means of high performance liquid chromatography. In experiments on isolated CS tissue, four AVP antagonists were characterized and their effects on electrically induced contractions in CS and CC strips were investigated. IR-AVP was found in CS and CC in amounts considerably higher than those found in circulating blood, suggesting that AVP is stored and/or synthetized locally. The AVP antagonists tested reduced contractions induced by AVP in CS and CC strips, but did not affect electrically induced contractions in these tissues. The results suggest that even if human penile erectile smooth muscles contain AVP, the peptide seems not to be released on electrical stimulation and consequently serves not as a contractile transmitter in these tissues.
EFFECT OF SPINAL ANESTHESIA ON ERECTION IN THE MONKEY. *Stefan C. Muller, *Mark R. Fahey, San Francisco, CA (Presentation to be made by Dr. M..tller) Five "chronic" rronkeys having electrodes :inplanted around the caven10us nerve for electro-erection were studied before and after spinal anesthesia at the level of L3/L4 (10-30 rrg Lidocaine 1.5% with Dextrose 7 .5%). Prior to spinal anesthesia, all rronkeys were sedated with Ketamine (10-15 rrg/kg im.) and intracavernous pressures were rreasured through a 21-gauge butterfly needle =nnected to a Statham transducer. Arterial blocxl pressures were repeatedly rronitored using a pediatric blocxl pressure cuff and a Doppler probe on the radial artery. Intracavernous pressure changes of electro-erection were recorded repeatedly before and after spinal anesthesia. The effect and level of spinal anesthesia was docurrented by paralyzed legs during light Ketamine sedation. After injection of Lidocaine, and with the IlDnkeys in supine position, the penis showed turrescence and elongation with very little pressure increase. Stimulation of the cavernous nerve showed the erectile response (intracavernous pressure) in direct relation to the peak systolic blocxl pressure. When stinulation was tenninated, the erection was markedly prolonged. In one nonkey, the intracavernous pressure went high above the systolic blocxl pressure, although a slight penile retraction could be observed. Obviously, there was an imbalance in the neurophysiology between turrescence and deturrescence factors. We assurre that blockade of the sympathetic nerve system caused prolonged erection, and that the unaffected intrinsic tone of the cavernous SllOOth muscle was responsible for the slight penile retraction, but increasing intracavemous pressure while the venous drainage system was caupressed.
376A