Synchronized electrical stimulation of the sympathetic and parasympathetic innervation of the bladder: facilitation of the initiation of micturition in the dog

Modulation of a dog's internal organ function by selective stimulation of the splanchnic nerve

The superficial regions of the dog splanchnic nerve were selectively stimulated with 33-electrode spiral cuffs in 11 circumferential groups of three electrodes to modulate the function of the innervated internal organs and glands. In two adult Beagle dogs under general anaesthesia, the cuffs were chronically implanted on the nerve trunks before the celiac ganglion. Superficial regions of the nerves were selectively stimulated for 15 s with biphasic, rectangular, current pulses (2 mA intensity, 200 micros duration, and 20 Hz frequency) which were delivered sequentially to the corresponding group of three electrodes. The results showed that Group no. 8 of three electrodes elicited the highest influence on pressure within the bladder. Namely, a decrease in pressure starting from 34.97 mmHg at the beginning of stimulation to 34.92 mmHg at the end of stimulation was observed. It was also shown that only Group no. 4 of three electrodes significantly modified the endocrine function of the pancreas. A considerable increase in glucagon secretion with a peak value of 47 pg/ml and an insignificant change in insulin secretion were also observed. The results of histological observations demonstrated that the use of the cuff was associated with a buildup of connective tissue encapsulation around the cuff as well as within it. However, functional deficits were not observed in the animal, and most of the fibers appeared to be histologically normal after stimulation. The results of this study clearly demonstrate that internal organs and glands can be selectively stimulated through the selective stimulation of innervating superficial regions of the autonomous peripheral nerve.

Dog as an animal model for neurostimulation

The dog provides an important model to study the effect of neural stimulation of different parts of the central and peripheral nervous systems. A multitude of experiments on neurostimulation and neuromodulation to ensure bladder evacuation have been conducted on dogs. The present article reviews the most prominent contributions in the English literature related to neurostimulation using the dog as an experimental model. The various modes of stimulation using dogs as a model and the rationale for their use as well as their shortcomings will be examined. The prominent anatomic features in the neural control of the bladder and the technical aspects involved in neurostimulation of the canine bladder will be reviewed.

Afferent and sympathetic innervation of the dome and the base of the urinary bladder of the female rat

The afferent and sympathetic innervation of different regions of the urinary bladder (bladder dome vs. bladder base) was examined in the female rat using simultaneous injections of two fluorescent tracers. Retrogradely labeled cells were found in the dorsal root ganglia (DRG; L1-L3 and L6-S1), the sympathetic chain (SC; T12-L6), the inferior mesenteric ganglia (IMG) and the major pelvic ganglia (MPG). There were very few double-labeled cells, indicating that the dome and the base of the bladder receive innervation (afferent or sympathetic) from separate and distinct neuronal populations. Most of the sympathetic innervation of the bladder arose from the SC (dome: 77%; base: 89%) and it was carried equally by the hypogastric and pelvic nerves. The distributions of SC postganglionic neurons innervating the dome and the base of the bladder were very similar. In contrast, the contribution of IMG neurons was almost entirely restricted to the dome of the bladder (22%), with less than 1% innervating the base. Tyrosine hydroxylase-immunoreactive (TH) neurons in the MPG displayed a strong sexual dimorphism. Many TH neurons were found in the male MPG, but very few in the female MPG. In the female, these TH neurons projected almost exclusively to the bladder base of the female rat and were responsible for 10% of the sympathetic innervation of the base. Less than 1% innervated the dome. Therefore, prevertebral ganglia (IMG and MPG) show a strong regional selectivity in the innervation of the bladder of the female rat. The possible functional implications of this organization are discussed.