Studies on desglycinamide arginine vasopressin and scopolamine in a modified/lever-touch autoshaping model of learning/memory in rats

doi:10.1016/0091-3057(87)90574-0

Pharmacology Biochemistry and Behavior

Volume 27, Issue 2, June 1987, Pages 307-315

https://doi.org/10.1016/0091-3057(87)90574-0 Get rights and content

Abstract

Vasopressin administration has been reported to improve acquisition and retard extinction of both conditioned avoidance and food-reinforced behavioral tasks. In the present experiment the effects of a vasopressin analog (DGAVP) and scopolamine (SCOP) were tested in an autoshaped lever-touch model of learning and memory. Rats were food-deprived to 80% of original body weights and tested in modular cages which contained a retractable lever that was presented on a random interval 48 sec schedule. The lever retracted after 15 sec or when it was touched, at which time one 45 mg food pellet was delivered. Subcutaneous injection of 10 μg/kg DGAVP 1 hr prior to acquisition and extinction sessions did not alter responding compared to saline controls. DGAVP at doses of 10, 20, and 30 μg/kg also failed to affect responding in a more difficult task which included an 8 sec delay between lever retraction and reinforcement. Homozygous Brattleboro rats, which are deficient in vasopressin, did not differ from normal heterozygous littermates in the acquisition of the lever-touch response. Intraperitoneal injection of SCOP (0.1–0.8 mg/kg) 30 min prior to testing caused a dose-related impairment of acquisition compared to saline controls, but did not alter responding in animals which had previously acquired the lever-touch response. These data suggest that manipulations of vasopressin do not affect, while SCOP impairs, the acquisition of a positively reinforced lever-touch response in rats.

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Cited by (11)

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1988, Neurotoxicology and Teratology
p-Xylene is a ubiquitous solvent and chemical precursor used in industry, gasoline, and household products. While the population at risk for exposure is thus quite large, little is known about its neurobehavioral effects. To evaluate the possibility that p-xylene affects cognitive behavior, male Long-Evans hooded rats inhaled p-xylene at concentrations of 0 or 1600 ppm, 4 hr per day for 1 to 5 days, and were evaluated after exposure on two learning tasks and a test of motor activity. Autoshaping was carried out across 5 successive days with p-xylene exposure in the morning followed by testing in the afternoon. For this test, the retraction of a single response lever on a variable-time 35-sec schedule was followed by delivery of a food pellet. When the force required to depress the lever was low (0.10 N), response acquisition was faster in animals having inhaled 1600 ppm p-xylene than in air-exposed controls. When the force was increased to 0.20 N, however, p-xylene-exposed rats acquired the response no faster than controls. In contrast, inhaled p-xylene at 1600 ppm suppressed response rates in an automaintained reversal learning paradigm without affecting reversal rate. Studies of motor activity showed that while vertically-directed activity was unaffected by p-xylene, horizontally-directed activity was increased by about 30% for the first 15 min of each daily 25-min test. This p-xylene-induced hyperactivity returned to control levels within each daily test and declined across the 5 daily tests, but was still evident on the fifth day. Rats tested 3.5 hr after termination of p-xylene inhalation were not less hyperactive than rats tested 0.5 hr after exposure. Increased horizontally-directed activity was not correlated across animals with the enhancement of autoshaping. These results were interpreted to indicate that p-xylene inhalation at 16 times the TLV induced hyperactivity and facilitated autoshaping by different means, and that the facilitation of autoshaping involved a change in response topography and not a direct effect on learning ability per se.
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1988, Pharmacology, Biochemistry and Behavior
The effects of nicotine (NIC) and scopolamine (SCOP) on radial maze acquisition were examined using an 8-arm radial maze. In Experiment 1, food-deprived Sprague-Dawley rats were trained to eat food pellets located at the ends of each arm of the radial maze without repeating arm choices. Both NIC (0.45 mg/kg, SC) and SCOP (0.25 mg/kg, IP) impaired acquisition when they were administered before, but not after the daily training sessions. Experiment 2 examined the effect of nicotine on working and reference memory in rats trained to a criterion of 3 correct choices out of the first 4 choices with only 4 of the 8 arms baited. NIC (0.1–0.45 mg/kg) had no effect on working memory (reentry into baited arms) or reference memory (entry into unbaited arms) errors. It is concluded that NIC impairs processes involved in the acquisition but not maintenance of radial maze performance. Neither NIC nor SCOP affects post-training consolidation processes.

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Studies on desglycinamide arginine vasopressin and scopolamine in a modified/lever-touch autoshaping model of learning/memory in rats

Abstract

Physiol Behav

Brain Res

Neurobiol Aging

Horm Behav

Brain Res

Physiol Behav

Physiol Behav

Brain Res

Pharmacol Biochem Behav

Behav Brain Res

Physiol Behav

Life Sci

Physiol Behav

Prog Brain Res

Pharmacol Biochem Behav

Eur J Pharmacol

Regul Pept

Neurosci Lett