Viscero-somatic reflexes following distension of urinary bladder in cats: Role of supraspinal neuraxis

Summary Viscero-somatic reflexes have been studied by recording monosynaptic reflexes following distension of the urinary bladder in intact, decerebrate and spinal animals. It was observed that the viscero-somatic responses following bladder distension are inhibitory in nature and this inhibition was highest in decerebrates and least in spinal animals. The site of viscero-somatic interaction probably lies in the bulbar area (supraspinal) and spinal cord.Acknowledgment. The work was carried out with the financial assistance of the Indian Council of Medical Research, Govt of India. We are thankful to A. T. Pradhan, Abott Laboratories (India) Pvt. Ltd. for a generous supply of Nembutal.     

Enhancement by pyridoxine of the action of diazepam on spinal presynaptic inhibition

Summary In spinal unanesthetized cats, pyridoxine pretreatment significantly enhanced the diazepam-induced increase in dorsal root potentials and dorsal root reflexes.Acknowledgments. This work was supported by a grant from the Lebanese National Research Council. The authors wish to thank Mr M. Shakarji for technical assistance in this investigation.     

Transplantation into the mammalian adult spinal cord

Summary Embryonic cerebral cortical tissue obtained from rat embryos of 15-day gestation was transplanted into the cervical spinal cord of adult rats. The cortical transplants survived, grew, and established connections with the host animal's spinal cord. In other animals, knife lesions were first made in the host's spinal cord, and then embryonic cortical tissue was transplanted into the site of the lesion. The cortical transplants in these animals were observed to become an integral part of the host animal's spinal cord.     

Neuropeptides in pelvic afferent pathways

Neurochemical and pharmacological experiments have raised the possibility that several neuropeptides including, vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), substance P, calcitonin gene-related peptide (CGRP), neurokinin A, cholecystokinin (CCK) and opioid peptides may be transmitters in afferent pathways to the pelvic viscera. These substances are widely distributed in: 1) nerve fibers in the pelvic organs, 2) visceral afferent neurons in the lumbosacral dorsal root ganglia and 3) at sites of afferent termination in the spinal cord. Double staining immunocytochemical techniques have shown that more than one peptide can be localized in individual visceral afferent neurons and that neuronal excitatory (VIP, substance P, CCK) and inhibitory peptides (leucine enkephalin) can coexist in the same afferent cell. Studies with the neurotoxin, capsaicin, indicate that peptidergic afferent pathways are involved in the initiation of central autonomic reflexes as well as peripheral axon reflexes which modulate smooth muscle activity, facilitate transmission in automatic ganglia and trigger local inflammatory responses.     

Neuropeptides in pelvic afferent pathways

Summary Neurochemical and pharmacological experiments have raised the possibility that several neuropeptides including, vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), substance P, calcitonin gene-related peptide (CGRP), neurokinin A, cholecystokinin (CCK) and opioid peptides may be transmitters in afferent pathways to the pelvic viscera. These substances are widely distributed in: 1) nerve fibers in the pelvic organs, 2) visceral afferent neurons in the lumbosacral dorsal root ganglia and 3) at sites of afferent termination in the spinal cord. Double, staining immunocytochemical techniques have shown that more than one peptide can be localized in individual visceral afferent neurons and that neuronal excitatory (VIP, substance P, CCK) and inhibitory peptides (leucine enkephalin) can coexist in the same afferent cell. Studies with the neurotoxin, capsaicin, indicate that peptidergic afferent pathways are, involved in the initiation of central autonomic reflexes as well as peripheral axon reflexes which modulate smooth muscle activity, facilitate transmission in automatic ganglia and trigger local inflammatory responses.     

Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles.

The Soleus muscle of the rat, 3--6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3--6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

Spielen die Eigenreflexe bei raschen Willkürkontraktionen eine entscheidende Rolle?

Summary A short time after a quick voluntary movement, there is no evidence of a monosynaptic reflex (Eigenreflex) following a stretch of the same muscle. Thus rhythms of voluntary movements may exist without interaction of stretch reflexes.     

Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles

Summary The Soleus muscle of the rat, 3–6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3–6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

Post-tetanic changes of bilateral dorsal root potentials evoked by stimulation of the cutaneous afferents.

In spinal cats following tetanic stimulation of the cutaneous nerve bilateral dorsal root potentials in the lumbar spinal cord are depressed. Because of differences between ipsi- and contralateral potentials, this depression can usually be evoked only on one side of the cord.     

Post-tetanic changes of bilateral dorsal root potentials evoked by stimulation of the cutaneous afferents

Summary In spinal cats following tetanic stimulation of the cutaneous nerve bilateral dorsal root potentials in the lumbar spinal cord are depressed. Because of differences between ipsi- and contralateral potentials, this depression can usually be evoked only on one side of the cord.     

Association of asymmetric unit membrane plaque formation in the urinary bladder of adult humans with therapeutic radiation

Summary Asymmetric unit membrane (AUM) is a component of the luminal membrane of urinary bladder in many species. In normal human adults it is inconspicuous, but it becomes prominent following incidental exposure to therapeutic irradiation.This work was supported by the Otho S.A. Sprague Memorial Institute.     

Association of asymmetric unit membrane plaque formation in the urinary bladder of adult humans with therapeutic radiation

Asymmetric unit membrane (AUM) is a component of the luminal membrane of urinary bladder in many species. In normal human adults it is inconspicuous, but it becomes prominent following incidental exposure to therapeutic irradiation.     

Paralysies révélatrices de la leucémie de Gross chez le rat

Summary Inoculation of Wistar CF rats with Gross virus induces in 86% of the animals a leukaemia which is associated, in nearly 50% of the cases, with a paralysis of the hind legs.This paralysis is due to the compression of the spinal cord by leukaemic cell infiltrates which develop in the lumbar area. No neurotropic virus has been found in these animals.     

Vestibular units during decompensation.

Typical modifications of the unitary discharge of vestibular units have been recorded following the transection of the spinal cord of hemilabyrinthectomized and compensated guinea-pigs. These results support the concept that the spinal cord is essential in the compensation of the symptoms resulting from a lesion of one labyrinth.     

The influence of pigmentation of rats and guinea-pigs on the ototoxicity of kanamycin and neomycin.

Following the finding that melanin pigment played a role in the accumulation of ototoxic drugs in the inner ear, an investigation was made of the possible influence of the pigmentation of animals on their susceptibility to the ototoxic effects of drugs. Hearing acuity was assessed by measurement of acoustic startle reaction. Preliminary experiments suggested that pigmented animals might be more likely to suffer hearing impairment following ototoxic drug administration. However, in a controlled study using rats treated with kanamycin, it was not possible to confirm this and albino animals appeared no less vulnerable than pigmented animals to kanamycin-induced deafness.     

Vestibular units during decompensation

Summary Typical modifications of the unitary discharge of vestibular units have been recorded following the transection of the spinal cord of hemilabyrinthectomized and compensated guinea-pigs. These results support the concept that the spinal cord is essential in the compensation of the symptoms resulting from a lesion of one labyrinth.Supported by a grant of CNR.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Summary Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform thoughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform throughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Organization of reflex responses elicited in man by muscle stretch applied to uni- and bi-functional muscles]

The organization of human forearm reflexes following the application of extension torque perturbations has been studied in three flexors of the elbow: brachioradialis (BR), biceps (B), and pronator teres (PT). Two of these flexors are also involved in wrist supination: (B) and pronation (PT). During the perturbation, the wrist was fixed at various angles: from full supination to full pronation. The results show that the amplitude of the reflex responses of B and PT is highly dependent on wrist position. By eliminating biceps length changes as a source of observed reflex variation, it has been shown that the normalized reflex amplitude of B increases by 300% when the wrist position is varied from full pronation to full supination. In contrast, the BR muscle has a reflex response which is independent of wrist position. These results are discussed in relation to the role of reciprocal innervation and the possible action of receptors encoding wrist angle.     

Possible role of GABA in the development of tolerance to alcohol

Summary Rat cerebellar GABA levels were reduced following 2 weeks alcohol administration. Animals also exhibited alcohol tolerance with an air righting reflex. This tolerance was mimiced by picrotoxin administration in control animals and was reduced in animals chronically administered alcohol by aminooxyacetic acid.This work was supported in part by a grant awarded under Public Law 93-282, Division of Addiction Services, Indiana Department of Mental Health, Indianapolis, Indiana, USA, Patrick J. V. Corcoran, M. D., principal investigator.