Reference

Pharmacological characteristics of dopamine receptors involved in the dual effect of dopamine agonists on yawning behavior in rats

Pharmacological characteristics of dopamine receptors involved in the dual effect of dopamine agonists on yawning behavior in rats. Protais, Philippe; Dubuc, Isabelle; Costentin, Jean (Lab. Pharmacodyn. Physiol., UER Med. Pharm. Rouen, Saint Etienne du Rouvray 76800, Fr.). Eur. J. Pharmacol., 94(3-4), 271-80 (English) 1983. CODEN: EJPHAZ. ISSN: 0014-2999. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 2 Increasing doses of apomorphine (APO) [58-00-4] induced the dose-dependent appearance of yawning in rats, at doses up to 0.1 mg/kg, the yawning disappearing at 0.1-0.6 mg/kg. A similar biphasic effect on yawning was obsd. with increasing doses of n-propylnorapomorphine [18426-20-5], piribedilmethanesulfonate [52293-23-9], S 584 [50602-50-1], bromocriptine mesylate [22260-51-1], lergotrile [36945-03-6], lisuride [18016-80-3], CQ 32084 [72782-54-8], and L-DOPA [59-92-7]. APO, n-propylnorapomorphine, piribedil, and CQ 32084 had similar ED50 on the induction of sniffing and on the disappearance of yawns. All the neuroleptics tested antagonized the yawns induced by 0.1 mg/kg APO. Increasing doses of haloperidol [52-86-8], chlorpromazine [50-53-3], mezilamine [50335-55-2], metoclopramide [364-62-5], and thioridazine [50-52-2] made the yawns reappear in rats injected with APO 0.6 mg/kg. The ID50 were similar to those for the antagonism of sniffing. On the other hand, increasing doses of clozapine [5786-21-0], (±)- [23672-06-2] or (-)-sulpiride [23672-07-3], veralipride [66644-81-3], and DAN 2163 [23694-17-9] did not make the yawns reappear in rats injected with 0.6 mg/kg APO although sniffing was antagonized. These results are discussed in terms of the ability of sulpiride, veralipiride, and DAN 2163 to distinguish between the dopamine (DA) receptors involved in the appearance of yawns at low doses of DA agonists and in their disappearance at higher doses. The decreased APO-induced yawning obsd. concomitantly with increased sniffing in rats with 6-hydroxydopamine-lesioned olfactory tubercles suggests that yawning and sniffing could be mutually exclusive.

Selection of dopamine antagonists discriminating various behavioral responses and radioligand binding sites

Selection of dopamine antagonists discriminating various behavioral responses and radioligand binding sites. Martres, M. P.; Sokoloff, P.; Delandre, M.; Schwartz, J. C.; Protais, P.; Costentin, J. (Unite Neurobiol., Cent. Paul Broca, Paris F-75014, Fr.). Naunyn-Schmiedeberg's Arch. Pharmacol., 325(2), 102-15 (English) 1984. CODEN: NSAPCC. ISSN: 0028-1298. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 2 The effect of a series of antipsychotics on the apomorphine [58-00-4]-induced facial stereotypies (sniffing and licking) and stereotyped climbing and also on brain dopaminergic receptor binding was tested. Of the antipsychotics tested, only some benzamides ((±)-sulpiride [23672-06-2], LUR 2366 [72135-20-7], and DAN 2163 [23694-17-9]) antagonized climbing at lower doses than sniffing or licking. 2062-78-4 and 57808-66-9 which are cas registry numbers of chemicals are mentioned. Using 3H-labeled apomorphine and doperidone [57808-66-9] as radioligands, the possibility that this discriminant potency might be related to a distinct affinity for 2 classes of dopaminergic receptors was investigated. From lesion and subcellular fractionation studies, 2 classes of binding sites were distinguished in the striatum which appear to be differentially localized, D-2 sites and D-4 sites. Whereas most of the dopaminergic antagonists antagonized the D-2 and D-4 receptors with similar affinities, the 3 benzamide derivs. with the largest selectivity in the behavioral tests displayed 2-3 fold higher affinity for D-4 than for D-2 sites. These results appear to support the existence of 2 classes of dopaminergic receptors, although a complete pharmacol. sepn. cannot be made. .