Joseph C. Hinsey

Sensory Components of the Phrenic Nerve of the Cat

Summary By degeneration of the somatic motor and sympathetic fibers in the phrenic nerve, it has been shown histologically that this nerve contains myelinated sensory fibers of different sizes and unmyelinated ones. The ratio of unmyelinated to myelinated sensory fibers is relatively high in 2 of the 3 phrenic nerves studied as compared to that reported for a motor branch of the femoral nerve.

Recollections About the Neurological Sciences with Emphasis on Neuroendocrinology

As I review my investigative career, I find that it has dealt with the anatomy (gross, microscopic, comparative), physiology, embryology, pathology, chemistry, and pharmacology of the nervous sytem as well as neuroendocrinology, which was an outgrowth of other interests in the neurological sciences. Some review of the institutions where I have been and the responsibilities there is indicated.

The rôle of the sympathetic nervous system in muscle tonus.

The left lumbar sympathetic trunk was removed through a median abdominal incision in cats. Autopsy showed the left trunk had been completely removed from the second lumbar to below the brim of the pelvis and that the right trunk was intact. After postoperative periods varying from 50 to 77 days, five of these cats were decerebrated by ligation of the basilar and both carotid arteries. No difference between the sound and the sympathectomized limb could be detected either as to posture or rigidity. Using a simple device, the pressure required to flex the limb was measured in ounces and the time required in minutes. The measurements were repeated several times on each cat and such differences as exist between the two sides, sometimes in favor of the normal side, sometimes against it, disappear when averages of the whole series of measurements are considered. Three other sympathectomized cats were given tetanus toxin, injecting equal quantities subcutaneously over the femoral trochanter in each hind leg. The degree of rigidity and the abnormal posture which developed in the two limbs were identical. These experiments show that the sympathetic nervous system is not responsible for exaggerated muscle tonus caused by decerebration or the action of tetanus toxin. The nerve to the vastus internus muscle is being studied to determine the effect of sympthectomy on its unmyelinated fiber content.

Regulation of Skin Temperatures after Lesions of Spinal Nerve Roots

Summary 1. Deafferentation of a cats forelimb does not lower the skin temperature of the footpad which may remain similar to the contralateral normally innervated one or may be warmer. 2. Deafferentation of a hindlimb may not affect the pad temperature, or it may be lowered or raised. 3. Any differences present in the fore-limbs or in the hindlimbs disappear after bilateral sympathectomy. 4. Section of the L6-L7 and S1-S2 ventral roots of a cat may not significantly affect the pad temperatures.