Influence of adrenergic receptor blockade on circulatory and metabolic effects of disordered neurotransmitter function in stroke patients.

Abstract

SUMMARY Cerebral hemispheric blood flow and metabolism were measured before and after therapy with intracarotid infusion of combined PBZ and PPL in IS patients with recent cerebral infarction. HBF was unaltered despite decrease in cerebral perfusion pressure. Cerebral hemispheric oxygen consumption and carbon dioxide production decreased while cerebral hemispheric lactate production increased.Biphasic cerebral uptake of tyrosine was observed during and immediately after PBZ and PPL infusion. CSF HVA increased, indicating altered DA turnover. CSF SHIAA levels also increased, suggesting altered SHT turnover after PBZ and PPL. Release of cyclic AMP from ischemic brain into cerebral venous blood seen in the steady state was abolished after therapy.Cerebral hemodynamic studies suggest a functional balance between monoaminergic neurogenic influences in the control of cerebral circulation. Imbalance of such controlling factors in ischemic brain may lead to paradoxical vascular responses to induced hypertension and hypotension. PBZ and PPL enhance such responses perhaps by increasing central neurotransmitter turnover and release.Further shift toward cerebral anaerobic metabolism may occur in ischemic brain following the use of phenoxybenzamine and propranolol.Worsening of neurological deficit occurred in four cases. Combined therapy with PBZ and PPL does not appear beneficial in the therapy of patients with recent stroke.

The locus coeruleus and cerebral metabolism: Recovery of function after cortical injury

“…Other investigators have found that PBZ increases the incidence of stroke, worsens neurological symptoms, and causes high mortality in an experimental stroke model (McGraw, Pashyan, & Wendell, 1976). Additionally, a clinical study with ischemIc or infarcted patients reported that a combined treatment with PBZ and PROP worsened neurological deficits in some patients (J. S. Meyer et al, 1976).…”

Cerebral blood flow in the monkey after focal cryogenic injury.

“…After the lesion was made, the exposed brain was again covered with saline-soaked cotton patties. When the electrodes had restabilized, we resumed measurement of CBF and A-VO 2 After the last measurement, each animal was killed with a rapid intravenous injection of a saturated solution of MgSO 4 . The calvarium was removed and the brain examined in situ with the electrodes in place.…”

Effect of prazosin on microvascular perfusion during middle cerebral artery ligation in the rat.

“…However, hemorrhage, which lowered cerebral flow to a similar extent with accompanying hypocapnia, led to an increase in the percentage of the capillary bed perfused. 10 The effect of adrenergic receptor blockade has been studied in patients with stroke by Meyer et al 23 and in cats after MCA occlusion by Little et al 24 Little et al 24 noted a protective effect of propranolol on ischemic brain tissue after 6 hours of partial ischemia. However, in a later study these authors were unable to find a reduction in infarct size in propranolol treated animals.…”

“…However, in a later study these authors were unable to find a reduction in infarct size in propranolol treated animals. Meyer et al 23 used a combination of propranolol and phenoxybenzamine to block both a-and /3-adrenoceptors in patients with stroke. They found an increase in the neurological deficit in four of their patients and no improvement in outcome in other patients receiving this therapy.…”