Carol McNamara

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In an attempt to assess the contribution of the NMDA receptor system to the development of cocaine self-administration, acquisition of intravenous self-administration (0.25mg/kg/infusion) was assessed in rats that received pretreatment with MK-801 (0.0, 0.1 or 0.25mg/kg). For control rats, reliable self-administration was obtained in 3-8 days of testing.(More)
Previously, we demonstrated that caffeine dose-dependently reinstated extinguished cocaine-taking behavior in rats. In the present study, we determined whether this effect of caffeine would extinguish with repeated exposures. Rats were first trained to self-administer cocaine intravenously. Once reliable self-administration was obtained, the pumps that(More)
Acquisition of cocaine self-administration (0.125, 0.25 or 0.5 mg/kg/infusion) was assessed in rats that had received prior exposure to either saline or amphetamine (2.0 mg/kg). Acquisition of self-administration was dose-dependent, with the highest dose leading to the shortest latency to reliably discriminate between depression of a lever that resulted in(More)
Acute exposure to methylphenidate (0.0, 5.0, 10.0, or 20.0 mg/kg) or amphetamine (0.0, 0.5, 1.0, 2.0, or 4.0 mg/kg) dose-dependently increased horizontal activity. The amphetamine-induced increase in activity was progressively augmented with repeated exposures over 7 days. In contrast, methylphenidate (20.0 mg/kg)-induced increases in activity became(More)
There is ample evidence for efferent cardiac denervation in patients after cardiac transplantation. However, little is known regarding the effects of the cardiac deafferentation that also results. We examined responses to graded lower-body negative pressure and thus cardiopulmonary baroreceptor unloading in 23 patients 3 to 12 months after cardiac(More)
We have examined the effects of the dopamine agonist bromocriptine (BEC) on the hormonal and hemodynamic response to graded lower body negative pressure (LBNP) and tilting in five normal volunteers. BEC blunted the plasma norepinephrine (NE), plasma renin activity (PRA), and aldosterone responses to both LBNP and tilting. The inhibitory effects of BEC on(More)
In the present work we have compared a pituitary LH extract and circulating LH from adult male rats (5 months old) with those from rats 10, 13, or 24 months old. The pituitary and circulating forms of LH prepared from old animals had a higher apparent molecular weight, judged by gel filtration, than LH preparations from younger animals. This difference may(More)
Mean arterial blood pressure, forearm vascular resistance, plasma norepinephrine, plasma renin activity and aldosterone responses to graded lower body negative pressure and tilt at 80 degrees were examined in 10 men with mild to moderate essential hypertension before and after 12 weeks of diltiazem (240 to 360 mg/day) therapy. Diltiazem therapy lowered(More)
To determine whether clonidine treatment affects cardiopulmonary baroreflex induced sympathetic activation, we assessed the hemodynamic and hormonal responses to lower body negative pressure (LBNP) before and after 3 weeks of treatment with low-dose (0.2 mg daily) clonidine in eight older (mean age, 62 years) patients with established mild-to-moderate(More)
Previous studies that measured reflex vasoconstrictor responses during isometric exercise have suggested that these responses were modulated by arterial and cardiopulmonary baroreflexes. The purpose of these experiments was to determine forearm vasoconstrictor responses to isometric handgrip alone and during two levels of cardiopulmonary baroreceptor(More)