EFFECTS OF AMYGDALOID STIMULATION ON EFFERENT ACTIVITIES OF THE VESICAL BRANCH OF THE PELVIC NERVE AND THE URETHRAL BRANCH OF THE PUDENDAL NERVE IN DOGS
1989 Volume 80 Issue 2 Pages 236-244
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1989 Volume 80 Issue 2 Pages 236-244
Experiments were performed to elucidate the effects of amygdaloid stimulation on the urinary bladder and external sphincter in 38 dogs anesthetized with ketamine and α-chloralose and immobilized with gallamine. The hypogastric nerves were severed in all dogs. The bladder was filled with Tyrode's solution under intravesical pressure maintained within a range of 15-20cmH2O.
The outflows of the pelvic vesical branch (PV) and pudendal urethral branch (PU) were recorded simultaneously with isotonic vesical contractions. Stimulation was applied through a unipolar platinum electrode (50μm, in diameter) inserted into the amygdala from the ventral surface of the exposed pyriform lobe.
When bladder contraction was elicited by amygdaloid stimulation, PV excitation and PU inhibition occurred simultaneously, but when the bladder was relaxed, PV inhibition and PU excitation appeared concomitantly.
The PV excitation (bladder contraction) was elicited from medial parts of the intermediate and medial principal nuclei and parts of the cortical and pericortical nuclei. Inhibition of PV (bladder relaxation) was induced from the medial nucleus, the central nucleus, lateral parts of the medial principal nucleus and parts of the pericortical nucleus.
Electrical stimulation was applied to the excitatory points at varied frequencies (2-100Hz). PV excitation and bladder contraction were produced at 10, 20 and 50Hz, but not at 2Hz. At 5 and 100Hz, the effects varied with the stimulating points. At the inhibitory points, PV inhibition and bladder relaxation were elicited at 10, 20 and 50Hz, but not at 2Hz. When bladder contraction was induced by amygdaloid stimulation, the increased PV and decreased PU appeared after latencise of 110-150msec and 80-114msec, respectively. On the other hand, when the bladder relaxation was elicited by the stimulation, the decreased PV and enhanced PU occurred after latencies of 60-120msec and 50-80msec, respectively.
These results suggest that the excitation and inhibition of the urinary bladder and the external urethral sphincter following amygdaloid stimulation are manifested through the hypothalamus, the pontine micturition center and the sacral segment of the spinal cord.
