Behavioral evidence for the rapid release of CNS serotonin by PCA and fenfluramine

Multiple 5-HT Receptors in Passive Avoidance Comparative Studies of p-Chloroamphetamine and 8-OH-DPAT

“…Although PCA also causes an acute release of dopamine (DA) (Crespi et al 1997;Henderson et al 1993;Johnson et al 1990;Ögren 1985b;Sharp et al 1986) as well noradrenaline (NA) (Ögren 1982; Ögren 1985a) in the rat brain, its behavioral effects are mediated primarily via serotonergic mechanisms (Adell et al 1989;Geyer 1996;Hutson and Curzon 1989;Trulson and Jacobs 1976). In support of this, the one-way active avoidance deficit by PCA was completely blocked when the rats were pretreated with 5-HT reuptake inhibitors zimeldine and fluoxetine but not by the NA uptake inhibitor desipramine (Ögren 1982).…”

“…During the exploration phase in the PA apparatus, the behavior of the animals was observed, and the presence or absence of the components of the serotonin (5-HT) syndrome (flat body posture, lower lip retraction, reciprocal forepaw treading, head weaving and twitches, wet-dog shakes, hind limb abduction, penile erection, and tremor) (Berendsen et al 1989;Grahame-Smith 1971;Jacobs 1976;Tricklebank et al 1984;Trulson and Jacobs 1976) and also the rearing frequency were noted.…”

“…In addition, 8-OH-DPAT and PCA also induce various behavioral effects; for example, modulate both general locomotor activity (Curzon 1990;Dourish et al 1985;Evenden and Angeby-Möller 1990;Hutson and Curzon 1989;, nociceptive thresholds (Hamon et al 1990;, and elicit a characteristic behavioral syndrome (5-HT syndrome) (Berendsen et al 1989;Jacobs 1976;Tricklebank et al 1984;Trulson and Jacobs 1976). However, the present and previous analysis allow us to conclude that the inhibitory effects of 8-OH-DPAT (Carli et al 1992;Misane et al 1998a;Riekkinen 1994) or PCA (Ögren 1985b;Santucci et al 1996) on PA retention cannot be simply attributed to these "nonlearning" factors.…”

“…The animals ( n ϭ 7-40, for details, see figure legends) were treated with the test compounds as described below. After the selected time interval following injection (day 1), rats were placed into the light compartment (with no access to the dark compartment) and allowed to explore for 2 minutes.During the exploration phase in the PA apparatus, the behavior of the animals was observed, and the presence or absence of the components of the serotonin (5-HT) syndrome (flat body posture, lower lip retraction, reciprocal forepaw treading, head weaving and twitches, wet-dog shakes, hind limb abduction, penile erection, and tremor) (Berendsen et al 1989;Grahame-Smith 1971;Jacobs 1976;Tricklebank et al 1984;Trulson and Jacobs 1976) and also the rearing frequency were noted.When 2 min expired, the sliding door was automatically opened by pressing a pedal, and the rats were allowed to cross over into the dark compartment. Once the rats had entered the dark compartment with all four feet, the sliding door was automatically shut, and an inescapable, constant current, scrambled shock (5 s duration, 0.6 mA) was delivered through the grid floor.…”

An in vivo dialysis and behavioural study of the release of 5‐HT by p‐chloroamphetamine in reserpine‐treated rats

“…Some or all of these components can be elicited by drugs which selectively release neuro{'al 5-HT, such as p-chloroamphetamine (PCA; Trulson & Jacobs, 1976;Kuhn et al, 1985), as well as by agonists (Hjorth et al, 1982;Tricklebank et al, 1985a,b;Smith & Peroutka, 1986).…”