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C A Greer

Publications and source records attributed to C A Greer.

60 records · Page 4Linked to original sources

Differential neurohumoral modulation of myoclonic and clonic seizures.

Differential effects of neuropharmacological drugs upon susceptibility to flurothyl-induced myoclonic and clonic convulsions were assessed in two selectively bred lines of mice. Dopaminergic drugs (apomorphine and haloperidol) only affected myoclonus, whereas cholinergic (pilocarpine and scopolamine), gabaergic (AOAA and bicuculline), and serotonergic (PCPA) compounds principally influenced clonus. Noradrenergic drugs (clonidine, phentolamine and sotalol), however, altered the expression of both types of seizures. The apparent differential neurohumoral modulation of myoclonus and clonus is discussed in light of previous suggestions that these behaviors have separate neural substrates.

Aminooxyacetic Acid↗

Methaqualone: tolerance and physical dependence in mice.

Tolerance and physical dependence was produced in C57Bl/6 male mice that had been exposed, for 36 days, to methaqualone in food pellets via an automated system. Tolerance was revealed in the reduction of sleep-times following intraperitoneal injection of methaqualone. Physical dependence was manifested as an alteration in neural sensitivity to flurothyl-induced convulsions.

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The effect of intravenous tissue-type plasminogen activator in a rat model of embolic cerebral ischemia.

Thrombolytic agents may be useful in the treatment of cerebral ischemia caused by arterial thrombosis or embolic occlusion. A trial of intravenous human tissue-type plasminogen activator (rt-PA) was carried out in seven male Sprague-Dawley rats subjected to embolic cerebral ischemia, with eight control animals. One-hour-old autogenous blood clot was injected into the internal carotid artery. A 30-minute infusion of 10 micrograms/kg/minute of rt-PA or saline followed. Areas of ischemia at two hours post-embolization were assessed by digital image processing of serial iodo-14C-antipyrine autoradiographic images. The volumes of "no-flow" (NF) and "low-flow" (LF) regions were calculated. One animal in each group suffered no detectable ischemia; the remainder had well-defined regions of middle and posterior cerebral artery ischemia. No animal sustained a hemorrhagic lesion. Treatment produced no noticeable effect on the patency of cervical vessels. Total NF and LF volumes were less for the treated group but did not reach statistical significance by t-test. In middle cerebral distribution sections, however, LF volume was significantly less (p less than 0.05) for treated animals (150 vs. 191 mm3), primarily due to a more significant decrease in LF volume in the anterior-middle cerebral overlap zone (47 vs. 90 mm3; p less than 0.025). Fibrinogen levels were not altered by drug treatment (p greater than 0.30).

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