A comparison of motor behaviours in groups of rats distinguished by their climbing response to apomorphine

Abstract

Administration of apomorphine hydrochloride (0.5 mg kg−1 s.c.) to adult male or female Wistar rats previously acclimatized to the test environment induced climbing behaviour in approximately 50% of animals examined. The proportion of animals climbing was related to age, being maximal at 8–9 weeks. Those animals showing an initial climbing response to apomorphine (0.5 mg kg−1 s.c), climbed when challenged with this dose of apomorphine on subsequent occasions. In ‘climbing’ animals the intensity of response was related to the dose of apomorphine administered; no dose‐response relationship was observed in ‘non‐climbing’ animals. No overall differences in the spontaneous motor behaviour of ‘climbing’ and ‘non‐climbing’ animals were apparent as assessed by measurement of spontaneous climbing behaviour, by holeboard activity, and by locomotor activity measured in either photocell cages or in a treadwheel. There was no overall difference in the ability of apomorphine to induce locomotor activity or stereotyped behaviour in ‘climbing’ and ‘non‐climbing’ animals. However, the administration of apomorphine induced rearing and treadwheel activity only in those animals classified as ‘climbers’. There was no difference between the number (Bmax) of specific [3H]‐spiperone binding sites or the dissociation constant (KD) in striatal or mesolimbic tissue preparations for ‘climbing’ and ‘non‐climbing’ rats. The ability of an animal to climb in response to apomorphine appears to be dependent on an ability to orient vertically, since this is a component of behaviour common to climbing, rearing, and treadwheel activity. The ability to climb does not appear to be related to differences in dopamine receptor numbers in brain or to the penetration of apomorphine into brain.

The paw test: a behavioural paradigm for differentiating between classical and atypical neuroleptic drugs

“…In a recent study, however, no difference was found between the classical neuroleptics haloperidol and chlorpromazine and the atypical neuroleptic thioridazine (Ljungberg and Ungerstedt 1985). Furthermore, the difficulty of this and other models using apomorphine to induce a behaviour is that the response of individual animals to apomorphine can vary greatly (Davis et al 1986). …”

The pharmacological characterisation of pilocarpine-induced purposeless chewing behaviour in the rat

“…Rupniak et al (1983) found that purposeless chewing could be induced in rats with physostigmine 0.5 mg/kg. Davis et al (1986) found that apomorphine-induced stereotyped behaviours in rats over the dose range 0.03 1.0 mg/kg SC. Secoverine antagonised oxotremorineinduced analgesia in mice, with an EDso value of 7 mg/kg IP (Zwagemaakers and Claasen 1980).…”

Psychoneuropharmacological activities and chemical composition of essential oil of fresh fruits of Piper guineense (Piperaceae) in mice

“…Effect of EOPG on apomorphine-induced climbing test. The method described by Davis et al (1986) was adopted with minor modification. The following scoring system was employed: 0 ¼all paws on cage floor; 1 ¼two paws placed on the side of the cage; 2¼ all paws off floor; 3 animal climbed and remain on the wall.…”