Joseph R Tobin

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Cognitive impairments in humans and animals have been linked to dysfunction of neurons in the basal forebrain cholinergic system (BFCS). Degeneration of these cells may be, in part, responsible for some of the cognitive deficits observed in Alzheimer's disease (AD). Although memory deficits are associated with lesions of the BFCS in rats, impairments in(More)
Nitric oxide (NO) is a candidate retrograde messenger involved in synaptic plasticity, and is linked to the cholinergic system in the brain. We examined the role of NO in the acquisition of visual and spatial discriminations by daily administration of either saline or 1-nitroarginine methyl ester (L-NAME), an NO synthase inhibitor. Brains were assayed for(More)
UNLABELLED Dexmedetomidine is a selective alpha(2)-agonist approved for sedation of critically ill patients. There is little information on the effects of dexmedetomidine on cerebral blood flow (CBF) or intracranial hemodynamics, despite considerable other pharmacodynamic data. We hypothesized that therapeutic doses of dexmedetomidine would decrease CBF.(More)
Peripheral nerve injury may lead to a chronic neuropathic pain state that results from an increase in excitability of central neurons. This central sensitization is mediated via an N-methyl-D-aspartic acid (NMDA) receptor and may involve the production of nitric oxide (NO). As NO is suggested to play a role in nociceptive transmission following nerve(More)
BACKGROUND Cholinergic agents produce analgesia after systemic and intrathecal administration. A retrospective review showed that intrathecal neostigmine was more potent in women than in men, suggesting a sex difference in this response. The purpose of this study was to determine whether such a sex difference exists in normal rats and to examine the(More)
The goal of the present set of studies was to characterize the in vitro binding properties and in vivo tissue kinetics for the vesicular acetylcholine transporter (VAcChT) radiotracer, [18F](+)-4-fluorobenzyltrozamicol ([18F](+)-FBT). In vitro binding studies were conducted in order to determine the affinity of the (+)- and (-)-stereoisomers of FBT for the(More)
Nitric oxide synthase (NOS) participates in the regulation of cerebral blood flow and neurotransmitter release and as a second messenger of glutamatergic and cholinergic systems. Developmental differences in NOS activity have been described in the rat, but not in a species with longer gestation and a larger, lobulated brain at birth. We assayed NOS activity(More)
Postoperative sensitivity to tactile stimuli differs as a function of age. In this study, we hypothesized that preoperative sciatic nerve block (SNB), by providing preemptive analgesia, would result in better analgesia than postoperative SNB in the young rat. With the paw incision model of postoperative pain, male Sprague-Dawley rats, aged 2 or 4 wk,(More)
UNLABELLED [18F](+)-4-fluorobenzyltrozamicol (FBT), which selectively binds to the vesicular acetylcholine transporter in the presynaptic cholinergic neuron, has previously been shown to be a useful ligand for the study of cholinergic terminal density in the basal ganglia with PET. The goal of this study was to assess the test-retest variability of [18F]FBT(More)
In the present study, the radiotracer [(18)F] (+)-4-fluorobenzyltrozamicol ((+)-[(18)F]FBT) and positron emission tomography (PET) were used to examine the vesicular acetylcholine transporter and determine if presynaptic cholinergic activity was altered with age in 23 rhesus monkeys that varied in age from 10 to 37 years. Binding of (+)-[(18)F]FBT in the(More)