Biphasic effects of ?9-tetrahydrocannabinol on variable interval schedule performance in rats

Abstract

Abstract. Four rats were trained to barpress for water reinforcement under a variable interval 60 sec schedule. 1XTine acute administrations of (--)Ag-trans-tetrahydrocannabinol, in amounts ranging from 0.25 to 16.0 mg/kg, produced doserelated effects on responding; overall response rate increased at lower doses, while higher doses produced ataxia and a complete suppression of responding. Increased response rates reflected changes both in response spacing and in the lengths of postreinforcement pauses. It was concluded that marihuana has a biphasic effect on variable interval water-reinforced behavior in rats. Key words: Marihuana (Cannabis) --(--)39-trans-Tetrahydrocannabinol(Ag-TttC) --Psychopharmacology --Operant Behavior --Schedule of Reinforcement.Both the unconditioned behavior and conditioned shock avoidance behavior of animals have been shown to be either increased or decreased by marihuana or a tetrahydroeannabinol (THC) derivative (e.g., Barry and Kubena, 1971 ; Garriott, King, Forney and Hughes, 1967;Holtzman, Lovell, Jaffe and Freedman, 1969;Kubena and Barry, 1970; Seheckel, Boff, Dahlen and Smart, 1968). A greater consistency between findings has been obtained with simple appetitive reinforcement operant conditioning schedules where the usual effect of marihuana has been to suppress the ongoing rate of response in rats and pigeons (e.g

Metabolic effects of cannabinoids in zebrafish (Danio rerio) embryos determined by 1H NMR metabolomics

“…In acute regimes, ∆ 9 -THC showed a biphasic response with increasing hyperactivity succeeded by suppression of activity as the dose increased. These findings are consistent with studies in rodents which reported a stimulation of locomotor activity by ∆ 9 -THC at low concentrations, and suppression at higher concentrations (Grisham and Ferraro 1972, Ferraro and Gluck 1974, Taylor and Fennessy 1977. A recent study (Freedland et al 2002) suggested that high concentrations of ∆ 9 -THC in adult rats decreased cerebral metabolism.…”

Single and combined effects of Δ9‐tetrahydrocannabinol and cannabidiol in a mouse model of chemotherapy‐induced neuropathic pain

“…As shown in Figure , both phytocannabinoids show very similar triphasic dose–response curves with two apparent peaks in efficacy, one within a dose range of 1.0–2.5 mg·kg −1 and the other within the 10–20 mg·kg −1 range. Biphasic effects of cannabinoids have been reported (Grisham and Ferraro, ; Kwiatkowska et al, ; Margulies and Hammer, ), and one study has reported triphasic effects of THC on locomotor activity across a wide range of doses (Sanudo‐Pena et al, ). In female mice dosed daily with CBD for 14 days, paclitaxel‐induced mechanical sensitivity was attenuated at the 10 mg·kg −1 dose but not the 5.0 mg·kg −1 dose (Ward et al, ).…”

The Effects of Smoked Marijuana on Progressive‐interval Schedule Performance in Humans

“…For example, with both FI (Brady & Balster, 1980;Elsmore & Manning, 1974;Stark & Dews, 1980) and VI schedules (Elsmore & Manning, 1974;Ferraro & Gluck, 1974;Grisham & Ferraro, 1972), low doses of marijuana increased response rates. Yet moderate doses of marijuana have no effect on the temporal distribution of responses on FI schedules (Frankenheim, McMillan, & Harris, 1971).…”