Hallucinogen-induced rotational behavior in rats

Acute effects of LSD on rhesus monkey operant test battery performance

The acute effects of LSD were assessed in rhesus macaques using behavior in several complex tasks designed to model aspects of time estimation, short-term memory and attention, motivation, learning, and color and position discrimination. The end points monitored included percent task completed, response rate, and accuracy. LSD (0.0003-0.03 mg/kg intravenously) significantly decreased percent task completed and accuracy in the time estimation task at doses < or = 0.003 mg/kg, but did not significantly affect response rate in this task at any dose tested. Accuracy in the short-term memory task was significantly decreased at the highest dose tested (0.03 mg/kg), but no other end points were affected in this task. Response rate was decreased in both the motivation and learning tasks at doses (0.01 and 0.003 mg/kg, respectively) lower than those affecting other end points. In the color and position discrimination task, only response rate was affected (0.01 and 0.03 mg/kg). These data demonstrate that in rhesus monkeys, performance of tasks believed to depend on aspects of time estimation and motivation are more sensitive to the acute disruptive effects of LSD than are tasks thought to model learning, short-term memory, and color and position discrimination.

The iminodipropionitrile (IDPN)-induced dyskinetic syndrome: behavioral and biochemical pharmacology

Chronic administration of iminodipropionitrile causes a persistent behavioral syndrome which is characterized by lateral and vertical head shakes, random circling, hyperactivity and increased acoustic startle response in rodents. These behavioral abnormalities are similar to those observed after the acute administration of serotonin (5-HT) and dopamine (DA) agonists, and of some peptides including thyrotropin-releasing hormone (TRH) and the enkephalins. The data available so far indicate that the 5-HT system which interacts with some other neurotransmitters such as DA and norepinephrine (NE) in both reciprocal and nonreciprocal ways may be primarily involved in the manifestations of this persistent dyskinetic syndrome. Preliminary evaluation of the peptidergic systems has also revealed possible involvement of opiate peptides in the IDPN-induced dyskinetic phenomena. More studies are needed to assess the role of specific molecular events which may occur at cortical, subcortical, and/or spinal levels to cause this interesting psychomotor syndrome.

Cocaine-induced rotation: sex-dependent differences between left- and right-sided rats

Cocaine elicited dose-related rotation (circling) in naïve rats. The maximum effect was greater than observed previously with other drugs. Overall, females were more sensitive to cocaine than males. However, right-biased females were more sensitive than left-biased females, whereas left-biased males were more sensitive than right-biased males. The results suggest that sex-dependent differences in brain asymmetry may be an important determinant of cocaine sensitivity.