Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

A single dose of prazosin (PRAZ), an alpha-1 noradrenergic (NA) antagonist, or clonidine (CLON), an alpha-2 NA agonist, transiently reinstates hemiplegia measured by beam walk (BW) performance in recovered rats 30 days after sensorimotor cortex contusion by traumatic brain injury (TBI; Feeney & Westerberg, 1990, Can J Psychol, 44, 233-252.). Two experiments addressed the issue of endurance of hemiplegia reinstatement. The first investigated changes in reinstated BW deficit dose-response curves to PRAZ or the beta NA antagonist propranolol (PROP) repeated at 1, 3, & 6 mos. after TBI. Rats were equally vulnerable to transient reinstatement by PRAZ, but not PROP, at all times post-injury. The degree of reinstatement was dose-dependent and correlated to the severity of the initial deficit 24 hrs. post-TBI. The second experiment determined if tolerance to reinstatement of BW deficits developed after 3 injections of PRAZ or CLON given at 3 hr intervals. No tolerance was observed as both groups remained equally disabled over the 9 hour period of BW testing. Recovery of locomotor ability is a fragile state, perturbable by commonly prescribed drugs such as selective antagonists to alpha-1 NA receptors. Funded by UNM RAC grant, NIMH grant T34-MH19101.

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Poster Number PAstibick0798
Keywords: brain injury, trauma, noradrenalin, norepinephrine, recovery