Animal experiment:

Rats[1]Voiding is studied in urethane-anesthetized (1.2 g/kg sc) or awake female Sprague-Dawley rats (250-300 g). In all experiments, control cystometrograms (CMGs) are recorded for ~2 h before intracerebroventricular and intravenous injection of vehicle or (±)-Epibatidine solutions. Dose-response curves are constructed by administering increasing doses of (±)-Epibatidine [0.001-1 μg in 1 μL intracerebroventricularly (icv); 0.001-1 μg in 200 μL iv] at 30-min to 2-h intervals. (±)-Epibatidine is administered ~30 min after vehicle (aCSF, 1 μL icv; or saline solution, 200 μL iv). Chlorisondamine (10 μg, 1 μL icv) is injected 10-30 min before (±)-Epibatidine via the intracerebroventricular route in some experiments to block the effect of the agonist. The intravesical pressure to induce micturition (PT), MVP, and intercontraction interval (ICI; the interval between voids or reflex bladder contractions) are measured and converted into percent change from control values[1].

(+)-AJ 76 hydrochloride is an antagonist of dopamine autoreceptor with pKi values of 6.95, 6.67, 6.37, 6.21 and 6.07 for hD3, hD4, hD2S, hD2L and rD2 receptors, respectively.

Dopamine receptor is a G protein-coupled receptor and mainly exists in the vertebrate central nervous system (CNS). Dopamine receptor is a receptor for dopamine and plays a critical role in memory, learning, pleasure, cognition, motivation and fine motor control.

(+)-AJ 76 hydrochloride is a dopamine receptor antagonist. In rats, AJ76 stimulated locomotor activity and increased the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) and HVA in brain, which were dopamine metabolites [1]. In rats injected with cocaine, (+)-A J76 increased the locomotor stimulation during the first 30 min. However, (+)-AJ76 inhibited the later more intense locomotor stimulation and cocaine-induced stereotypies [2]. In vivo, (+)-AJ76 induced dopamine release mainly through interaction with dopamine receptors in the terminal regions of the A9 and A10 dopaminergic fibers. However, (+)-AJ76 increased the level of DOPAC via the somatodendritic autoreceptors [3].

References:
[1].  Kullingsjo H, Carlsson A, Svensson K. Effects of repeated administration of the preferential dopamine autoreceptor antagonist, (+)-AJ76, on locomotor activity and brain DA metabolism in the rat. Eur J Pharmacol, 1991, 205(3): 241-246.
[2].  Piercey MF, Lum JT, Hoffmann WE, et al. Antagonism of cocaine's pharmacological effects by the stimulant dopaminergic antagonists, (+)-AJ76 and (+)-UH232. Brain Res, 1992; 588(2): 217-222.
[3].  Waters N, Hansson L, Lofberg L, et al. Intracerebral infusion of (+)-AJ76 and (+)-UH232: effects on dopamine release and metabolism in vivo. Eur J Pharmacol, 1994, 251(2-3): 181-190.