Michael R. Lynch

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When treated chronically with haloperidol, rats show progressively enhanced behavioral suppression, mimicking the delay of onset seen clinically with neuroleptics. To investigate potential neurochemical mechanisms underlying this delay, low-dose apomorphine treatment was administered after withdrawal from 21 days of 0.1 mg/kg haloperidol, to probe for(More)
  • M R Lynch
  • 1992
Negative symptoms have been associated with structural impairment in the PFC, and hypothesized to arise from a central hypodopaminergic substrate. Corticofugal PFC neurons, which are inhibited by VTA DA innervation, exert a tonic excitatory modulation on DA activity in the NAS. Lesions of ascending DA forebrain projections "uncouple" the functional link(More)
Animals in the present investigation were trained for conditioned place preference by pairing the non-preferred compartment of a two chamber apparatus with either 1.5 mg kg-1 D-amphetamine or 0.05 mg kg-1 scopolamine. Some of the amphetamine-conditioned rats were injected with 0.05 mg kg-1 scopolamine as an acute treatment on the test day which followed(More)
Five halogenated hydrocarbons (chloral; trichloroethylene; 1,2-dichloroethylene; 1,2-dichloroethane and 1,1,2-trichloroethane) were evaluated in the taste aversion paradigm to determine thresholds for producing aversion effects. Comparisons were made between threshold determination for acute and repetitive conditioning trials. All of the compounds produced(More)
  • M R Lynch
  • 1997
1. Negative symptoms of schizophrenia are characterized by amotivation, anhedonia and anergia. These aspects of the symptom profile can be modeled by D3 agonism in animal behavioral models. 2. Serotonergic systems have been implicated in pathophysiologic substrates for this disorder; most notably, in deficit state schizophrenia, as newer 'atypical'(More)
The effect of direct intrastriatal injection of three organophosphate cholinesterase inhibitors, DFP (diisopropylphosphorofluoridate), soman (pinacolyl methylphosphonofluoridate) and sarin (isopropyl methylphosphonofluoridate) has been studied on locomotor activity in the rat. The degree of ChE inhibition has been monitored in the striatum, as well as in(More)
Early postlesion amphetamine-induced contralateral rotation has been linked to intraneuronal dopamine (DA) accumulation and transmitter release associated with axonal degeneration. Animals in the present study sustained severe unilateral depletion of striatal DA with or without a near-complete loss of ipsilateral mesolimbic DA. Contralateral rotation to 1.0(More)
In Experiment 1 four groups (N = 10) of individually housed mice were given access to deionized water for 30 min daily. When fluid consumption stabilized, they were given 30-min access to a 0.3% saccharin solution. This was followed by oral doses of 3, 10 or 30 mg/kg trichloromethane (TCM) or the vehicle (Emulphor). Beginning 24 hr later the subjects were(More)