investigation into the CSFabsorption in cats

Cerebrospinal fluid [CSF], its secretion, circulation and absorption have been the subject of recent researches. There is a general agreement that the main site of CSF secretion is in the choroids plexus. However, the main absorption site is controversial. Some believe that arachnoid granulations are the principle sites of CSF absorption. In this study, different locations of CSF absorption in cats are investigated. 2 ml [100 mg], of ferrous dextran was injected into the subarachnoid compartment of seven cats. After 15 days the animals were euthanized, and the central nervous system [CNS] and its relative tissues were analyzed for any iron amlumulation. Several tissue samples were taken and stained with Prussian blue and Hernatoxylin-eosin. The light microscopic study of different tissues showed amlumulation of the tracer in olfactory and optic nerves, dorsal root ganglia as well as spinal nerve roots. The main locations of CSF absorption were the spinal nerve roots and their surrounding lymphatic tissue. There is reason to believe that some endothelial fenestrate within these roots were involved in this process

Antiallodynic Effects of Acupuncture in Neuropathic Rats

Peripheral nerve injury often results in abnormal neuropathic pain such as allodynia or hyperalgesia. Acupuncture, a traditional Oriental medicine, has been used to relieve pain and related symptoms. However, the efficiency of acupuncture in relieving neuropathic pain is not clear. The aim of this study was to investigate the anti-allodynic effects of acupuncture through behavioral and electrophysiological examinations. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves, under pentobarbital anesthesia. The acupuncture experiment consisted of four different groups, one treated at each of three different acupoints (Zusanli (ST36), Yinlingquan (SP9), and a sham-acupoint) and a control group. Behavioral tests for mechanical allodynia and cold allodynia were performed for up to two weeks postoperatively. Extracellular electrophysiological recordings were made from the dorsal roots using platinum wire electrodes. Mechanical and cold allodynia were significantly reduced after acupuncture treatment at the Zusanli and Yinlingquan acupoints, respectively. Electrophysiological neural responses to von Frey and acetone tests were also reduced after acupuncture at the same two acupoints. These results suggest that acupuncture may be beneficial in relieving neuropathic pain.

Antiallodynic Effects of Acupuncture in Neuropathic Rats

Peripheral nerve injury often results in abnormal neuropathic pain such as allodynia or hyperalgesia. Acupuncture, a traditional Oriental medicine, has been used to relieve pain and related symptoms. However, the efficiency of acupuncture in relieving neuropathic pain is not clear. The aim of this study was to investigate the anti-allodynic effects of acupuncture through behavioral and electrophysiological examinations. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves, under pentobarbital anesthesia. The acupuncture experiment consisted of four different groups, one treated at each of three different acupoints (Zusanli (ST36), Yinlingquan (SP9), and a sham-acupoint) and a control group. Behavioral tests for mechanical allodynia and cold allodynia were performed for up to two weeks postoperatively. Extracellular electrophysiological recordings were made from the dorsal roots using platinum wire electrodes. Mechanical and cold allodynia were significantly reduced after acupuncture treatment at the Zusanli and Yinlingquan acupoints, respectively. Electrophysiological neural responses to von Frey and acetone tests were also reduced after acupuncture at the same two acupoints. These results suggest that acupuncture may be beneficial in relieving neuropathic pain.

Drematomal somatosensory evoked potentials (DSSEP) in patients with proved lumbosacral radiculopathies

Se llevó a cabo el estudio de potenciales evocados dermatómicos en 14 pacientes con afectación probada de raíces L5 o S1 o ambas unilateralmente. El estímulo se produjo en el área de piel correspondiente a la metamera deseada y el registro se efectuó en la corteza parietal de recepción contralateral. Los resultados fueron comparados con un grupo control sano, se observó que la técnica fue capaz de identificar a la lesión a través de dos tipos de hallazgos, uno fue el retraso en la latencia de la onda N1 y el segundo la ausencia de respuesta evocada

Effects and site of action of a single-breath of 100% CO2 on the monosynaptic reflexes in cats.

A single breath of 100% CO2 produces depression of the monosynaptic reflexes, recorded from L7 or S1 ventral root, after stimulation of the Posterior Biceps and Semitendinosus nerve (PBST) in anaesthetised cats. As the depression could not be attributed to the J-reflex(1), the possible site of action of the CO2 induced depression of monosynaptic reflexes was worked out. PBST nerve threshold did not change after CO2 introduction and the depression persisted in paralysed cats under controlled ventilation, thus eliminating the possibility of movement effect of the spinal cord due to tachypnoea. Spinal cord sections at the level of L1 and C1 abolished the depression, whereas the depression persisted in the decerebrate preparation. Thus it is concluded that a single-breath of 100% CO2 depresses the monosynaptic reflexes at the supraspinal level. Blood gas tensions (PO2 and pCO2) measured before and after CO2 introduction showed a shortlasting increase in pCO2 and not much significant change in pO2 compared to the long lasting depression of monosynaptic reflexes.