Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
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Magnocellular neuroendocrine cells (MNCs) of the supraoptic (SON) and paraventricular nuclei of the hypothalamus (PVN) are critical to survival since they are involved in the regulation of body water and cardiovascular function. Previous in vivo glutamate excitotoxicity studies have revealed that these nuclei do not succumb to glutamate, ibotenate or NMDLA exposure. To determine if SON and PVN MNCs are also resistant to ischemia we examined the reliability of two stroke models in preventing blood flow to these regions. Deeply anesthetized adult male rats were randomly assigned to one of three groups: 1) a four blood vessel occlusion group (4BVO) subjected to electrocauterization of both vertebral arteries and ligation of both common carotid arteries (CCA) for 10-30 min; 2) a middle cerebral artery (MCA) occlusion group subjected to permanent middle cerebral and ipsilateral CCA occlusion and transient contralateral CCA occlusion for 3 hr; 3) two control groups which were sham-operated as rats in group #1 or 2 but not subjected to arterial occlusion. During continued occlusion, rats were transcardially perfused with phosphate-buffered saline (PBS) followed by PBS containing 1.0% india ink. Histological examination of brains using cresyl violet counterstaining revealed that india ink failed to penetrate the SON and PVN only after MCA occlusion. In separate experiments rats were allowed to survive for 1-3 days post-surgery, were tested for neurological deficits, perfused with 4% paraformaldehyde under deep anesthesia and their brains examined. Our preliminary findings indicate that MCNs of the SON and PVN (but not hippocampal neurons) remain viable in both the 4BV and MCA groups.

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Poster Number PAhussein0796
Keywords: glutamate, neuroendocrine, excitotoxicity, stroke, vasopressin