THERMAL SENSATION IN THE BLADDER

It has been pointed out in an earlier paper by Nathan and Smith (1951) that " it is not yet definitely known whether the bladder mucosa is sensitive to thermal stimuli ". As a review of the literature has shown that there is no generally accepted opinion on the presence or absence of such sensation, the present investigation was undertaken. Guyon (1887) stated that one could feel in the bladder definitely whether liquids were hot or cold. Von Frankl-Hochwart and Zuckerkandl (1906) wrote that " the delicate sensitivity of the bladder to thermal stimuli is well known ". Zimmermann (1909) investigated the sensation by means of passing a urethral catheter on himself and running through it into the bladder fluids at temperatures of 00 C. and 500 C. ; he found that temperature was appreciated in the distal 2 to 3 cm. of the male urethra, but nowhere more proximally in the urethra, nor in the bladder. Muller (1919) reported that one of his colleagues, who investigated thermal sensation on his own bladder, found no sensation evoked by temperatures as different as 00 C. and 450 C. Waltz (1922), using a double-walled, glass urethral catheter, to avoid thermally stimulating the urethra, came to the conclusion that the bladder is insensitive to thermal stimulation. He also applied menthol to the mucosa; this caused no sensation, whereas, when it is applied to the skin, it stimulates cold spots, causing a sensation of cold. Moore (1924) investigated bladder sensation by passing " knobbed applicators" along the urethra; the sensitivity to thermal stimuli was examined by passing through a cystoscope such an instrument, consisting in this case of a glass tip 2 cm. by 4 mm. on a steel wire, which had previously been immersed in water at 60° C. and 150 C. He concluded that " heat was perceptible in every instance in the normal bladders . Cold was not as readily detected as heat ". Dees and Langworthy (1935) expressed the opinion that there is " a crude recognition of temperature in the mucosa"; and Langworthy, Kolb, and Lewis (1940) held the view that the bladder mucosa is " slightly responsive to heat, cold, and touch ". McLellan (1939) stated: " Thermal sensory nerve endings are present and the patient is generally aware of heat or cold and variations in the temperature. The bladder differs from other abdominal viscera in that it has the presence of thermal and tactile sensory endings ". McLellan and Goodell (1943) later investigated thermal sensation by permitting fluid to pass into the bladder through a urethral catheter; they found that fluid at 450 C. was felt to be hot, and fluid at 00 C. " very cool ". Band (1950) stated: " The bladder wall can distinguish between the hot and cold lotion employed for lavage ". As nearly all investigators passed liquids at various temperatures into the bladder through the urethra, it is possible that the disagreement concerning the observations may have arisen from neglecting the fact that the urethra is sensitive to thermal stimuli. As stimuli applied to the bladder are usually referred to the urethra, it is easy to see that the subjects being investigated might have been able to tell the temperature of the liquids, without being able to tell whether they experienced the sensation in the bladder or the urethra. This criticism applies least to Moore and Waltz, but they reported opposite findings.