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Biomedical subjects

R L Kitchell

Publications and source records attributed to R L Kitchell.

At least 19 recordsLinked to original sources
PubMed1992

Dorsal nerve root origins of the cutaneous nerves of the feline pelvic limb.

The dorsal root origins of cutaneous nerves supplying the feline pelvic limb were determined electrophysiologically in 11 cats. Cutaneous nerves were surgically exposed and the presence or absence of an evoked potential in response to stimulation of individual dorsal roots was noted. The dorsal cutaneous branches of L3-L5 and S3, and the lateral cutaneous branch of L3 each arose solely from their parent spinal nerves. The L7, S1, and S2 dorsal cutaneous branches had multiple dorsal root origins. The lateral cutaneous femoral nerve originated from L3-L6 dorsal roots in 4 patterns of origin, and the saphenous nerve originated from L4-L6 dorsal roots in 2 patterns of origin. The lateral and caudal cutaneous sural nerves originated from L6-S1 roots in 2 and 3 patterns, respectively. The lateral and medial plantar nerves arose from L6-S2 roots in 4 and 2 patterns, respectively. The superficial and deep peroneal nerves originated from L6-S1 roots in 2 and 3 patterns, respectively. The caudal cutaneous femoral nerve or its branches arose from L7-S3 in 8 origin patterns. The dorsal nerve of the penis and the superficial perineal nerve arose from L7-S3 and S1-S3 roots, respectively, each in 4 patterns. A subtle correlation between plexus type and dorsal root origins of the cutaneous nerves was noted.

Animals↗
PubMed1991

Brood patch innervation and its role in the onset of incubation in the turkey hen.

The source of innervation to the brood patch in turkey hens was determined by recording the electrophysiological activity of cutaneous nerves while manually stimulating various regions of the skin. The entire area of the brood patch was innervated by eight nerves, arising from thoracic vertebra 3 to synsacrothoracic vertebra 1. To determine whether afferent input from the brood patch influenced egg production or incubation behavior, hens were bilaterally denervated prior to photoinduced egg production. Denervated hens visited nests the same number of times, but stayed on the nest for less total time than controls by the fourth week of photostimulation. Serum prolactin levels rose in control hens but not in denervated hens. Egg production was maintained in the denervated hens but not in controls. None of the denervated hens displayed incubation behavior. This experiment supports the view that peripheral nervous input plays a role in the onset of incubation behavior.

Animals↗
PubMed1991

Spinal root origin of the radial nerve and nerves innervating shoulder muscles of the dog.

The ventral spinal root origin of the radial nerve, its muscle branches, and brachial plexus nerves which supply shoulder and thoracic musculature was determined in the dog. Electrophysiological signal averaging techniques measured evoked potential from specific ventral spinal roots to individual muscle nerves. The entire radial nerve received input from the sixth cervical (C6) through the second thoracic (T2) spinal roots. The most significant (p less than .05) input to triceps brachii came from C8 while the deep ramus of the radial nerve received its largest input from C7. The brachiocephalicus, suprascapular, and subscapular nerves all received their most significant (p less than .05) innervation from C6. Approximately 90% of the evoked potential to the axillary nerve originated from C7. The thoracodorsal nerve received most of its innervation from ventral roots C7 and C8. The lateral thoracic nerve which innervates the cutaneous trunci muscle was supplied by ventral roots C8-T2. Examination of innervation patterns suggests that only modest variation of spinal root input to specific nerves occurred between individual dogs.

Animals↗
PubMed1991

Electrophysiologic studies of the cutaneous innervation of the pelvic limb of male dogs.

The area of skin supplied by the afferent fibers in one cutaneous nerve is called the cutaneous area (CA) for that nerve. The CA of peripheral branches of lumbar and sacral spinal nerves responsive to the stimulation of hair follicle mechanoreceptors were mapped in 27 dogs. The amount of overlap among the CA was similar to that found for other CA of the body. The CA of peripheral branches of the sciatic nerve were restricted to the lateral, cranial, and caudal aspects of the pelvic limb distal to the stifle. The CA of the saphenous nerve was located on the medial side of the limb, except for a small area located on the lateral side of the crus. The distal part of the CA of the saphenous nerve was completely overlapped in the hind paw by branches of the superficial peroneal nerve laterally and the medial plantar branch of the tibial nerve medially. The CA for the deep peroneal nerve was located on the dorsal surface of the webbing between digits 2 and 3 and the adjacent skin of these digits. The CA of the plantar branches of the tibial nerve were small in comparison with the diameter of the nerve, suggesting that these branches contained nerve fibers supplying other, deeper structures in the hindpaw and that damage to these nerves would interfere with cutaneous sensation in only a small region on the plantar surface of the hindpaw. Knowledge of the CA of the various branches of the sciatic nerve allows more accurate localization of injury to the sciatic nerve or its branches by using areas of anesthesia.

Animals↗
PubMed1990

Binocular dissecting microscopic studies on the density of toruli tactile in the La Mancha goat.

The Merkel cells and associated nervous terminal plates have been called toruli tactiles (TT). These structures can be ubiquitously seen on the shaved hairy skin after staining with a methylene blue solution. Four La Mancha goats of both sexes were examined for the density of TT. TT were visually located under a binocular dissecting microscopic (14x) and then the number of TT in the field was directly counted. The density of TT in different corporal areas of the body surface was estimated from the mean of several two-cm square samples of skin. The results obtained are as follows: The mean number per two-cm square on the whole body surface ranged from 10.06-11.36 in the male specimen and from 12.98-14.32 in the female specimen. The density of TT was rather high in the temporal and buccal areas, on the neck, chin and cranial breast, and on the lateral surface of the arm, thigh and leg. Density was moderate in the fronto-parieto-occipital area (female), on the loin and buttocks, in the upper costal, lower caudo-costal, xiphoid-umbilical and umbilical-pubic areas, and on the lateral surface of the forearm. TT were absent or very few in number on the nose and chin, the scrotum, caudal-pubic area of males, the udder, the vulva, and the digitorum manus et pedis.

Animals↗
PubMed1990

Spinal nerve root origin of the median, ulnar and musculocutaneous nerves and their muscle nerve branches to the canine forelimb.

The contribution individual ventral spinal nerve roots made to the canine median nerve, ulnar nerve, musculocutaneous nerve, and their muscle nerve branches was determined electrophysiologically. Each spinal nerve root was sequentially stimulated. Utilizing quantitative signal averaging techniques, the evoked potential was measured at each tested peripheral nerve. Evoked potential to the median nerve originated from the seventh cervical spinal root (C7) through the second thoracic spinal root (T2) with most input from C8 and T1. The ulnar nerve received evoked potential from C7-T2. Although T1 provided the major input to both the median and ulnar nerves, the relative contribution of T1 was greater in the ulnar nerve. The musculocutaneous nerve received input from ventral spinal roots C6-T1 with C6 and C7 providing most of the evoked potential. The ventral spinal roots which supplied the bulk of the evoked potential to a particular muscle nerve were consistent between individual dogs. Variation of evoked potential input was greatest from spinal roots which supplied less than 10% of the total potential.

Animals↗
PubMed1989

Preservation of striated-muscle urethral sphincter function with use of a surgical technique for perineal urethrostomy in cats.

It has been reported that perineal urethrostomy resulted in impairment of striated-muscle urethral sphincter function in male cats, as measured by urethral pressure profilometry and electromyography (EMG). Our study was undertaken to describe and evaluate a surgical technique for perineal urethrostomy that reduces trauma to the urethral branches of the pudendal nerve. Perineal urethrostomy was performed on 10 healthy neutered cats after demonstrating that they had normal urethral sphincter function by urethral pressure profilometry (maximal urethral closure pressure [MUCP] = 151 +/- 52 cm of water) and EMG activity at the level of the striated-muscle sphincter before surgery. All cats had normal urethral sphincter function 1 week (MUCP = 194 +/- 19 cm of water, EMG activity present) and 3 weeks (MUCP greater than 200 cm of water, EMG activity present) after surgery. These results indicated that preservation of the urethral branches of the pudendal nerve during urethrostomy preserved striated-muscle urethral sphincter function.

Animals↗
PubMed1989

Motor fibers in the canine distal caudal cutaneous sural nerve--dual innervation of the hind limb plantar muscles.

The function of the communicating branch of the distal caudal cutaneous sural (DCCS) nerve to the tibial nerve was investigated in 7 adult dogs and was found to contain the motor component of this nerve. This function was studied by direct visualization of the contraction of the hind limb plantar muscles and by direct electrophysiologic recording of motor unit action potentials in these muscles, following stimulation of the DCCS nerve. Contraction of all of the mm. interossei, the mm. lumbricales, the m. adductor digiti quinti and the m. adductor digiti secundi was observed with the stimulation of either the tibial or the DCCS nerves, although there was a qualitative variability in the plantar muscles exhibiting the strongest contraction with stimulation of the latter nerve. This communicating branch was not found in one of the experimental dogs, suggesting some individual variability in the DCCS nerve anatomy and subsequent function. This study conclusively demonstrated that the canine DCCS nerve contains both motor and sensory nerve fibers, which is similar to this nerve in the rat, but anatomically and functionally different to that in the human and the cat.

Anatomy, Comparative↗
PubMed1988

Sexual behavior of male dairy goats: effects of deafferentation of the genitalia.

The following study examines the effects of deafferentation of the penis, scrotum, prepuce and adjacent cutaneous surfaces on the development of mounting behavior in male dairy goats. Ten males underwent surgical deafferentations and 10 males received sham operations at 8 to 12 weeks of age. Mounting and other sexual behaviors were monitored while subjects were cohabiting with male and female penmates and when individually exposed to estrous females. Denervated males mounted penmates less frequently than sham controls and lacked vigorous thrusting behavior. When exposed to estrous females denervated goats did not exhibit the normal progression from shallow to deep thrusting with successive mounts and failed to attain intromissions and ejaculations. However, frequency of mounting was similar to that of controls when the latter were prevented from attaining intromissions. It was concluded that sensory feedback from the genitalia and surrounding cutaneous areas is not required for the initiation of leg-kicking behavior in male dairy goats but plays an important role in the development and maintenance of normal patterns of thrusting behavior. Because it was not possible to determine the rate at which reinnervation occurred, the extent to which mounting behavior depends on sensory feedback could not be determined.

Afferent Pathways↗
PubMed1988

Spinal nerve root origins of the cutaneous nerves of the canine pelvic limb.

The spinal nerve root origins of the cutaneous nerves innervating the canine pelvic limb were determined in 12 barbiturate-anesthetized, healthy dogs by stimulating the dorsal roots L1-S3 and recording the evoked-action potentials from each cutaneous nerve. The dogs were then euthanatized, identification of each dorsal root and cutaneous nerve was verified by dissection, and the type of lumbosacral plexus (prefixed, median fixed, or postfixed) was determined. With one exception, the dorsal cutaneous branches and lateral cutaneous branches of L1-L3 originated only from their corresponding spinal nerve roots. The genitofemoral nerve received afferent fibers predominantly from L3-L4 nerve roots. The lateral cutaneous femoral nerve originated from L3-L5 nerve roots, and the saphenous nerve from L4-L6 nerve roots. The proximal caudal cutaneous sural nerve originated from L6-S1. The lateral cutaneous sural nerve originated from L5-S1; the deep and superficial fibular nerves arose primarily from L6-L7. The distal caudal cutaneous sural nerve originated predominantly from L7-S1, and the medial cutaneous tarsal nerve originated from L6-S1. The medial plantar nerve originated predominantly from L6-S1 roots, whereas the lateral plantar nerve originated from L6-S2 roots. The middle clunial nerve received afferent fibers primarily from S1-S2; the caudal clunial nerve received fibers from S1-S3. The caudal cutaneous femoral nerve originated predominantly from L7-S2. The dorsal nerve of the penis originated predominantly from S1-S2, and the superficial perineal nerve originated from S1-S3. One dog had a prefixed plexus, 8 dogs had median-fixed plexuses, and 1 dog had a postfixed plexus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Neurophysiologic maps of the cutaneous innervation of the external genitalia of the ewe.

The area of skin supplied by the afferent fibers in a peripheral nerve is called the cutaneous area (CA) of that nerve. The CA responsive to movement of wool or hair in the genital regions were mapped in 17 ewes, with the identifications of the peripheral nerves and of the spinal nerves contributing to the pudendal plexus being checked at necropsy. Differences were found in the origins and extent of CA of the cutaneous branches from the sacral plexus. The CA of the caudal rectal nerves and of a nerve that passed caudally between the caudal vertebrae and the ventral sacrococcygeus muscle lay lateral to the anus and in the adjacent skin of the tail. The CA of the proximal cutaneous branch and of the distal cutaneous branch from the pudendal nerve (or plexus) overlapped craniocaudally (by approx one-half) the CA of the distal cutaneous branch extending ventrally and ending just caudal to the ipsilateral mammary gland. The deep perineal nerve innervated the skin immediately lateral to the anus and vulva. The dorsal nerve of the clitoris innervated hairs on the ipsilateral half of the vulva. Other fibers in the pudendal nerve were presumed to pass into the mammary branch of the nerve. They innervated the skin ventral to the vulva, the ipsilateral mammary gland, and (in some ewes) areas of the skin cranial to the mammary gland. The CA of the genitofemoral nerve included the ipsilateral teat and the inguinal fossa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Mechanoreceptor response to mechanical and thermal stimuli in the glans penis of the dog.

In the dog, we isolated 126 mechanoreceptive afferent fibers of the A-delta myelinated fiber class from the dorsal nerve of the penis using microdissection and extracellular electrophysiological techniques. Receptive fields on the glans penis were stimulated with a computer-controlled mechanostimulator and Peltier effect thermostimulator. The great majority of units were categorized as either rapidly adapting (RA) or slowly adapting (SA) and were located primarily proximally and distally, respectively, on the glans. In comparison to values from other glabrous skin regions in other species, mean displacement and force thresholds of penile mechanoreceptors were high, whereas the mean velocity thresholds were low. SA units, generally poor encoders of static displacement, were distinguishable into two types based on static response firing pattern but were not homologous to either the SA I or SA II mechanoreceptors found in other skin regions. Fifty-five units were given simultaneous mechanical and thermal stimulation. Very few units responded to pure thermal stimulation or increased their discharge frequency to skin cooling. Warm receptive-field temperatures between 35 and 43 degrees C increased mechanical sensitivity, measured by displacement and velocity coding functions, in almost all units tested. We conclude that canine penile mechanoreceptors, capable of encoding a variety of skin movements when the penis is warm, provide the spinal cord with the sensory input necessary to drive the spinal sexual reflexes. However, many appear to be at least physiologically different from mechanoreceptors native to other skin areas.

Animals↗
PubMed1987

Neurophysiologic maps of cutaneous innervation of the external genitalia of the ram.

The area of skin innervated by the afferent fibers in a peripheral nerve is called the cutaneous area (CA) of that nerve. Mapping of those areas that were responsive to movement of wool/hairs in the genital region of 18 anesthetized rams, combined with subsequent identification of spinal nerves and dissection of the pudendal nerve plexus, indicated considerable differences in the extent of the CA and the origins of cutaneous branches from the pudendal plexus. The CA of the proximal and distal cutaneous branches of the pudendal nerve (or plexus) overlapped craniocaudally by approximately one-half, and the latter included most of the skin of the ipsilateral half of the scrotum. The CA of the deep perineal and caudal rectal nerves lay immediately adjacent to the anus. The CA of the scrotal branches of the pudendal nerve were restricted primarily to the scrotum. Fascicles in the dorsal nerve of the penis irregularly supplied CA along the length of the prepuce and consistently supplied the cranial free end of the prepuce. The CA of the ventral cutaneous branches of the caudal thoracic spinal nerves, the first 2 or 3 lumbar spinal nerves, and the genitofemoral nerve extended to the midline of the prepuce. Overlapping of CA was extensive, especially on the prepuce.

Animals↗
PubMed1987

Neurophysiologic maps of cutaneous innervation of the hind limb of sheep.

The area of skin supplied by afferent fibers in a peripheral nerve is called the cutaneous area (CA) of that nerve. The CA of hind limb nerves that were responsive to movement of wool/hairs were mapped neurophysiologically in 25 barbiturate-anesthetized sheep. The CA of the dorsal cutaneous branches of the caudal lumbar spinal nerves and of the sacral spinal nerves extended over the lateral aspect of the thigh. The CA of the lateral cutaneous femoral nerve was restricted to the stifle region, that of the saphenous nerve did not reach the digits, that of the deep peroneal nerve lay between the 3rd and 4th digits, and that of the lateral plantar nerve was confined to the lateral aspect of the 4th digit. The CA of the superficial peroneal nerve enveloped the dorsal, medial, and lateral aspects of the distal portions of the hind limb. In some sheep, the boundaries of the CA of the superficial peroneal nerve were juxtaposed caudally in such way that the medial plantar nerve did not have an autonomous zone. Differences in sizes of the CA resulted in corresponding differences in the overlap between adjacent CA and concomitant differences in the sizes of autonomous zones.

Animals↗
PubMed1986

Rapidly and slowly adapting mechanoreceptors in the glans penis of the cat.

Sixty-one single mechanoreceptive fibers were surgically isolated from the dorsal nerve of the penis in anesthetized, mature, and sexually intact male cats. Impulse activity was recorded extracellularly. Receptive fields on the glans penis were stimulated with an accurate computer controlled mechanostimulator. Thirty-four units were categorized as rapidly adapting (RA) based on the absence of a response to sustained skin displacement. The remaining were slowly adapting (SA) units responding to sustained displacement. Most of the SA units were located in the distal smooth glans whereas RA units predominated in the proximal spiny glans. Displacement thresholds were significantly lower for RA units. All units encoded indentation velocity although the SA units were better suited to discriminate slowly moving stimuli. In addition, SA units encoded sustained displacement amplitude. Male cats with a denervated glans penis display disoriented mounting behavior disabling intromission. The presence of distally located SA mechanoreceptors suggests they may be the primary penile proprioceptors, mediating, along with the RA mechanoreceptors, successful completion of intromission.

Animals↗
PubMed1984

Pain perception and alleviation in animals.

In the last 2 decades there have been substantial advances in our knowledge of the scientific basis of the mechanisms of pain. Nociceptors or pain receptors are widespread in the skin and tissues of animals; chemical mediation of nociceptor excitation may provide a key for understanding the peripheral phenomena related to pain. The expression of pain in animals involves multiple ascending and descending branches, as well as specialized pain-signaling mechanisms in the spinal cord. The importance of these different pathways varies with species and circumstances. Endogenous neural systems in the brain stem and forebrain including both opioid and nonopioid mechanisms may modulate the central transmission of nociceptive signals in animals. Noxious stimuli mediate a variety of different functions; each animal has a consistent response to noxious stimuli or a consistent pattern of escape from pain. As we better understand the mechanisms of pain, the humane treatment and alleviation of pain in experimental animals can be placed on a much firmer scientific basis.

Afferent Pathways↗