Application of 4-aminopyridine (4AP, 50 microM) to combined slices of adult rat hippocampus-entorhinal cortex-induced ictal and interictal epileptiform discharges, as well as slow field potentials that were abolished by the mu-opioid agonist [D-Ala2,N-Me-Phe4,Gly-ol5] enkephalin (DAGO, 10 microM) or the GABAA receptor antagonist bicuculline methiodide (BMI, 10 microM); hence, they represented synchronous GABA-mediated potentials. Ictal discharges originated in the entorhinal cortex and propagated to the hippocampus, whereas interictal activity of CA3 origin was usually recorded in the hippocampus. The GABA-mediated potentials had no fixed site of origin or modality of propagation; they closely preceded (0.2-5 sec) and thus appeared to initiate ictal discharges. Only ictal discharges were blocked by the antagonist of the NMDA receptor 3,3-(2-carboxypiperazine-4-yl)propyl-1-phosphonate (CPP, 10 microM), whereas the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM) abolished all epileptiform activities. The GABA-mediated potentials continued to occur synchronously in all regions even after concomitant application of CNQX and CPP. [K+]o elevations were recorded in the entorhinal cortex during the ictal discharge (peak values = 13.9 +/- 0.9 mM) and the synchronous GABA-mediated potentials (peak values = 4.2 +/- 0.1 mM); the latter increases were presumably attributable to postsynaptic GABAa-receptor activation because they were abolished by DAGO or BMI. Their role in initiating ictal activity was demonstrated by using DAGO, which abolished both GABA-mediated synchronous potentials and ictal discharges. These data indicate that NMDA-mediated ictal discharges induced by 4AP originate in the entorhinal cortex; such a conclusion is in line with clinical evidence obtained in temporal lobe epilepsy patients. 4AP also induces GABA-mediated potentials that spread within the limbic system when excitatory transmission is blocked and may play a role in initiating ictal discharge by increasing [K+]o.
Abbreviations & Acronyms A = adrenergic/noradrenergic BBB = blood-brain barrier DA = dopamine DLTN = dorsolateral tegmental nucleus DO = detrusor overactivity GABA = gamma-amino-butyric acid Glu = glutamate. GPi = globus pallidus internus IML = intermediolateral cell column L = lumbar LC = locus ceruleus LUT = lower urinary tract LUTS = lower urinary tract symptoms MPOA = medial preoptic area MSA = multiple system atrophy NBM = nucleus basalis Meynert OAB = overactive bladder PAG = periaqueductal gray matter PBN = parabrachial nucleus PD = Parkinson's disease PMC = pontine micturition center PVN = paraventricular nucleus S = sacral SNc = substantia nigra pars compacta SNr = substantia nigra pars reticulata STN = subthalamic nucleus T = thoracic TUR-P = transurethral prostate resection of the prostate VTA = ventral tegmental area ZI = zona incerta Abstract: Bladder function of patients with Parkinson's disease alters significantly: the majority of patients have overactive bladder (urinary urgency/frequency) with little or no post-void residuals. This seems to be the result of an altered brain-bladder relationship, as in Parkinson's disease, the frontal-basal ganglia D1 dopaminergic circuit that normally suppresses the micturition reflex is altered. The pathophysiology of the bladder dysfunction in Parkinson's disease differs from that in multiple system atrophy; therefore, it might also aid in differential diagnosis. The effects of levodopa, the major drug to treat motor dysfunction, on the bladder in Parkinson's disease vary significantly; therefore, add-on therapy is often required. Anticholinergic drugs are the first-line treatment, with particular care for cognitive function in elderly patients. The second-line treatment includes serotonergics drug, desmopressin and others. Newer modalities include deep brain stimulation that improves the bladder in Parkinson's disease; and botulinum toxin is promising, particularly in difficult cases. These treatments might be beneficial in maximizing the patients' quality of life.
An infant who suffered acute subdural hematoma due to minor head trauma twice in a short period is presented. Each subdural hematoma, showing high density on computed tomographic scanning, resolved with unusual rapidity, resulting in full recovery after nonsurgical management. The mechanism of this rapid resolution of each hematoma was thought to be participation of cerebrospinal fluid secondary to a tearing of the arachnoid membrane.
Limited attention has been paid to the relationship between urinary symptoms or urodynamic findings and motor disorders in Parkinson's disease (PD). We aimed to correlate pressure-flow urodynamic parameters with video-gait analysis parameters in PD. We recruited 41 patients with PD (25 men and 16 women; age, 70.6 ± 8.5 years; H & Y motor grading: 2 [range, 1-3]; disease duration: 4 years [range, 1-7]; taking levodopa 300 mg/day [range, 100-400]). All patients underwent pressure-flow urodynamics (parameters: first sensation, bladder capacity, detrusor overactivity [noted in 24 patients], and Watts factor [WF]) and video-gait analysis (parameters: time and number of strides for 5-m gait [simple task] and time for timed up and go [complex task]). Statistical analysis was made by Mann-Whitney's U-test for analyzing the relation between detrusor overactivity and gait as well as Spearman's rank-correlation coefficient test for analyzing the relation between the remaining parameters and gait. We found no relation between filling-phase urodynamics (detrusor overactivity, first sensation, and bladder capacity) and video-gait analysis parameters. By contrast, we found a significant relation between voiding-phase urodynamics (WF, reflecting detrusor power) and all three video-gait analysis parameters (reflecting lower-half bradykinesia and loss of postural reflex) in our PD patients (P < 0.01). The close relation between the WF and motor disorders in the present study suggests that, though clinically mild, a weak detrusor in PD might have a central origin. We should follow postvoid residual volume carefully in PD patients with advanced gait disorder, because postvoid residual volume might increase in such patients.
A rare case of epidural hematoma of the clivus is reported in an 11-year-old girl involved in a traffic accident which caused a severe hyperextension injury. Only one similar case has been reported in the literature. The mechanism for the formation of the hematoma of this region is discussed.
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