dynorphins and Arteriosclerosis

Thromboembolic phenomena and transient ischaemic attacks (TIA) are considered the basis of ischaemic pathologies. The aim of the present research is to investigate the involvement of k-opioid receptors in cerebral blood flow (CBF) impairment which results in experimental stroke or dietary atherosclerosis in rabbits. CBF measurement showed a significant decrease in rabbits submitted to embolization and/or atherosclerosis. Binding studies showed that massive cerebral ischaemia and atherosclerosis produced a significant increase in the number of k-opioid receptors (Bmax), without changing (KD) affinity values. In conclusion, the results obtained seem to indicate that the increase in k-opioid receptors might play a crucial role in a common cerebral biochemical mechanism both in ischaemic and atherosclerotic pathologies.

Topics: Animals; Arteriosclerosis; Brain Ischemia; Cerebral Cortex; Cerebrovascular Circulation; Diet, Atherogenic; Dynorphins; Electroencephalography; Evoked Potentials, Somatosensory; Kinetics; Lipids; Rabbits; Receptors, Opioid, kappa

Recently it has been suggested that endogenous k-opioid receptors may have a physiopathological role in ischemia induced neurodegeneration. The aim of this research is to show that in experimental thromboembolic (obtained mechanically using microspheres injected in the carotid) and atherosclerotic pathologies (obtained through a special diet) there is a common mechanism which involves mediation by dynorphine and the receptor compartment considered. The results, obtained using receptor binding techniques, showed a statistically significant increase in the number of k-opioid receptors (Bmax) without variations in the affinity (Kd) for the 3H dynorphine. We can therefore support the hypothesis that these changes in the modulation of the dynorphinergenic system may be part of a mechanism causing early cerebrovascular damage which results from embolic insults and is a consequence of such metabolic risk factors as are activated by atherogenesis.

Topics: Animals; Arteriosclerosis; Brain Ischemia; Cerebral Cortex; Diet, Atherogenic; Dynorphins; Electroencephalography; Kinetics; Lipids; Microspheres; Rabbits; Receptors, Opioid; Receptors, Opioid, kappa; Thromboembolism