TY - JOUR
T1 - Inhibition of pudendal reflexes in spinal rats
T2 - Reassessing the role of serotonin
AU - Holmes, Gregory M.
AU - Bresnahan, Jacqueline C.
AU - Beattie, Michael S.
N1 - Funding Information:
This study was supported by the Paralyzed Veterans of America SCRF Grant #1883-01 and NIH research grant NS-#31193. The authors wish to thank Dr. G.E. Hermann for comments on the manuscript. Technical assistance was provided by J.H. Komon, Jr., R.L. LoVerso-Toth, C.A. Tovar, and M.J. Van Meter.
PY - 2001
Y1 - 2001
N2 - The effects of serotonin (5-HT) and thyrotropin-releasing hormone (TRH) on penile reflexes were investigated in intact and spinally transected male rats. Doses of intrathecal 5-HT (0.0, 1.13, 2.26, 11.3, 22.6, and 113.0 nmol), in a range previously shown to inhibit pudendal reflexes in anesthetized spinal preparations, prolonged the latency to the first penile erection in awake intact rats. However, these doses also provoked hyperreactivity and vocalization. Doses of intrathecal TRH (100 and 500 pmol) that effectively inhibited penile erection in intact animals were less effective in spinalized animals. Finally, a combination of subthreshold doses of TRH (100 pmol) and 5-HT (4.0 nmol) at a ratio known to affect other TRH/5-HT-mediated circuits significantly extended erection latency in animals with spinal transections. These data suggest that 5-HT and TRH are both involved in the inhibitory circuits regulating penile erection, either through corelease onto the same population of cells or through independent release onto different populations of neurons.
AB - The effects of serotonin (5-HT) and thyrotropin-releasing hormone (TRH) on penile reflexes were investigated in intact and spinally transected male rats. Doses of intrathecal 5-HT (0.0, 1.13, 2.26, 11.3, 22.6, and 113.0 nmol), in a range previously shown to inhibit pudendal reflexes in anesthetized spinal preparations, prolonged the latency to the first penile erection in awake intact rats. However, these doses also provoked hyperreactivity and vocalization. Doses of intrathecal TRH (100 and 500 pmol) that effectively inhibited penile erection in intact animals were less effective in spinalized animals. Finally, a combination of subthreshold doses of TRH (100 pmol) and 5-HT (4.0 nmol) at a ratio known to affect other TRH/5-HT-mediated circuits significantly extended erection latency in animals with spinal transections. These data suggest that 5-HT and TRH are both involved in the inhibitory circuits regulating penile erection, either through corelease onto the same population of cells or through independent release onto different populations of neurons.
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U2 - 10.1016/S0031-9384(01)00512-1
DO - 10.1016/S0031-9384(01)00512-1
M3 - Article
C2 - 11564452
AN - SCOPUS:0034838101
SN - 0031-9384
VL - 74
SP - 57
EP - 64
JO - Physiology and Behavior
JF - Physiology and Behavior
IS - 1-2
ER -