Growth factor dependent cholinergic function and survival in primary mouse spinal cord cultures.

In primary embryonic spinal cord cultures, synaptic transmission can be conveniently studied by monitoring radiolabeled neurotransmitter release or by recording of electrophysiological responses. However, while the mature spinal cord contains an appreciable number of cholinergic motoneurons, cultures of embryonic spinal cord have a paucity of these neurons and release little or no acetylcholine upon stimulation. To determine whether the proportion of cholinergic neurons in primary mouse spinal cord cultures can be augmented, the effects of several classes of growth factors were examined on depolarization- and Ca(2+)-evoked release of choline/acetylcholine (Ch/ACh).

Cytotoxic actions of palytoxin on aortic smooth muscle cells in culture.

Palytoxin (PTX), isolated from a zoanthid of the genus Palythoa, is the most potent marine toxin known. Intoxication by PTX leads to vasoconstriction, hemorrhage, ataxia, muscle weakness, ventricular fibrillation, pulmonary hypertension, ischemia and death. In this study, clonal A7r5 rat aortic smooth muscle cells were used to study the mechanism of PTX-mediated cytotoxicity.

Primary cell culture for evaluation of botulinum neurotoxin antagonists.

The actions of botulinum neurotoxin (BoNT) were studied on evoked release of the neurotransmitter glycine in primary mouse spinal cord cells. 3[H]-glycine was taken up by cells in physiological solution and released by depolarization with 56 mM K+ in the presence of 2 mM Ca2+. Release of 3[H]-glycine was found to be inhibited by BoNT serotypes A, B and E with similar potency ratios to those observed in the acutely isolated mouse diaphragm muscle.

Reduced acetylcholine receptor density, morphological remodeling, and butyrylcholinesterase activity can sustain muscle function in acetylcholinesterase knockout mice.

Nerve-evoked contractions were studied in vitro in phrenic nerve-hemidiaphragm preparations from strain 129X1 acetylcholinesterase knockout (AChE-/-) mice and their wild-type littermates (AChE+/+). The AChE-/- mice fail to express AChE but have normal levels of butyrylcholinesterase (BChE) and can survive into adulthood. Twitch tensions elicited in diaphragms of AChE-/- mice by single supramaximal stimuli had larger amplitudes and slower rise and decay times than did those in wild-type animals.

Development of a Guinea pig model for low-dose, long-term exposure to organophosphorus nerve agents.

An animal dosing model and related maximum tolerated dose (MTD) were developed for repeated exposures in guinea pigs to three organophosphorus chemical warfare nerve agents (CWNA). Male animals were injected subcutaneously with sarin (GB), soman (GD) or VX once a day (Monday through Friday) for 2-, 4-, or 13-weeks. An initial 13-week study for each CWNA employed doses of vehicle (normal saline), 0.