Forskolin and 8-cyclopentyltheophylline synergistically facilitate the neuronal activity in the CA2 area of rat hippocampus via cAMP and non-cAMP cascades / 生理学报

High level of adenosine A1 receptor-like immunoreactivity has been found in the CA2/CA3a region of adult rat hippocampus, but its roles in the neuronal activity or signal propagation in hippocampus and its intracellular cascade remain to be studied. In this study, we examined the relation between adenosine-3',5'-cyclic monophosphate (cAMP) cascade and suppression of synaptic transmission by endogenous adenosine through adenosine A1 receptor in the CA2 area. In transverse hippocampal slice, maximal electrical stimulation of the hilus region (0.6 mA) only evoked small population spikes (PSs) in the CA2 area (0.5 mV). In the presence of forskolin (20 micromol/L), a direct adenylate cyclase activator, PSs in CA2 were increased to 1.1 mV. When 8-cyclopentyltheophylline (8CPT, 2 micromol/L), an adenosine A1 receptor antagonist, was added in the presence of 20 micromol/L forskolin, PSs with an average amplitude of 4.7 mV were recorded in the CA2 area, much higher than the sum of the amplitude of PSs in the presence of forskolin and 8CPT alone. To test whether this synergistic potentiation results from the additive activation of cAMP cascade, the cAMP content in hippocampal slices was measured with enzyme immunoassay (EIA). Results showed that 8CPT did not increase the cAMP content in CA2 with or without forskolin. Co-application of forskolin and Ro 20-1724, a cAMP-specific phosphodiesterase-IV inhibitor, only increased PSs in CA2 to 1.3 mV but increased cAMP content by 4.4 times. On the other hand, co-application of 8CPT and 1, 9-dideoxyforskolin, a forskolin analog which has no effect on adenylate cyclase, did not mimic the synergistic effect of 8CPT and forskolin on PSs in CA2. These results indicate that up-regulation of adenylate cyclase activity and inhibition of adenosine A1 receptor activity synergistically facilitate the neuronal activity in the CA2 area and the effect of adenosine A1 receptor antagonist is via non-cAMP cascade. These data also suggest that acting on adenosine A1 receptors, endogenous and extragenous adenosine/adenosine A1 agonist(s) inhibit neuronal activity through different pathways.

An experimental study of the neuroprotective effect of FK506 on acute spinal cord injury in dogs / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the neuroprotective effect of FK506 on acute spinal cord injury in dogs.</p><p><b>METHODS</b>Acute spinal cord injury model was made with the Allen technique. Animals were randomly divided into 3 groups. Group A (n = 8) was the control group and received operation but no therapy, while group B and C (n = 8) received a single dose of FK506 (0.18 mg/kg and 0.3 mg/kg, respectively) administered with an arterial duct 2 h after spinal cord injury (SCI). Spine MRI, neurological function, histopathological examination of injured spinal cord and immunohistochemical examination of expression of NF(200) in neurons and GFAP in astrocytes were assessed at certain time after injury.</p><p><b>RESULTS</b>Neurological function score of group C and B was better than that of group A (P < 0.05), with significance between group C and A, while no significance between group B and A statistically. The signal scope of spinal cord injury on MRI in group C was the smallest among all the groups, and the signal scope in group B was smaller than that in group A, which was directively associated with the neurological outcome. The expression of NF and GFAP was significantly higher in group C than in group A (P < 0.05), but without statistical significance between group B and A.</p><p><b>CONCLUSION</b>Local administration of FK506 (0.3 mg/kg) possesses neuroprotective effect on acute spinal cord injury, which can improve neurological function recovery and attenuate secondary spinal cord injury. Local administration of FK506 possesses a dosage-effect relation.</p>

Observation of the foramen of Monro on magnetic resonance imaging and its clinical significance / 中华全科医师杂志

Objective To study the localization of the foramen of Monro on magnetic resonance image (MRI) and its clinical significance.Methods Cranial MRI was observed for 30 normal healthy subjects to study their location,shape and size of the foramen of Monro,as compared to those in 22 patients with hydrocephalus and 14 cases with tumor around their foramen.Results The the foramen of Monro is located between the fornix and the anterior part of thalamus in the normal healthy subjects,with a transverse diameter of 2.8 mm and a vertical diameter of 2.1 mm in average on MRI.Y-shaped structure is formed between their bilateral the foramen of Monro and the 3rd cerebral ventricle.Very obvious changes in shape and size of the foramen of Monro can be observed in patients with hydrocephalus,which sometimes can integrated with the 3rd cerebral ventricle and lateral ventricle,forming a"rabbit-head sign".Meanwhile, imaging of the foramen of Monro varied in patients with tumor around the foramen,depending on its location and size.Conclusions The foramen of Monro has a relative constant position in the brain.Changes in its position,size and shape are important signs suggesting intracranial lesions.An individualized operation plan for a patient should be determined based on those changes.

Clinical application anatomy and endoscopic views of interventricular foramen / 中华显微外科杂志

Objective To study the clinical application anatomy of interventricular foramen and offer a base for operation.Methods Interventricular foramens were observed in 15 adult cadaveric brainThirty- two patients of obstructive hydrocephalus were operated to observe the structure of interventricular foramen un- der neuroendoscope.Results Interventricular foramen was a poriform structure which consists of fornixan- terior pole of thalamencephalon and choroid plexus and was a oval shape in most of themThe plane of the fo- ramen was a included angle with the median sagittal planeThe septal veinthalamostriate veinthalamen- cephal and even the floor of third ventricle could be observed clearly in endoscope.At the same timewe found the foramen had a significant change in obstructive hydrocephalus.Conclusion The interventricular foramen has a simple relatively structure but a variation on size and shape especially in obstructive hydroceph- alusA clearly comprehension of it's structure and adjacent is a base to microsurgery and endoscopic surgery on the foramen.