Spontaneous climbing behaviour of mice, its measurement and dopaminergic involvement

Measurement of spontaneous climbing behaviour of mice, made in Mouse Climbing Monitors which used photocell detection of vertical movements, was most reliable and intense when made over a 40 min period using two mice per cage and taking readings before 2:00 p.m. The climbing response was antagonised by low doses of the neuroleptics (-)-sulpiride and spiroperidol, and by low doses of the dopamine agonists apomorphine, N-n-propylbenzo(f)quinoline, N-n-propylbenzo(g)quinoline and 2-di-n-propylamino-5,6-dihydroxytetralin; N,N-dipropyldopamine was less effective. Higher doses of the dopamine agonists induced climbing. The inhibition afforded by apomorphine was partially antagonised by (-)-sulpiride and spiroperidol (at doses which do not in themselves modify spontaneous climbing) but not by prazosin or yohimbine. Bilateral electrolesions of the caudate-putamen, nucleus accumbens or tuberculum olfactorium attenuated spontaneous climbing for the first 5-9 postoperative days, the accumbens lesions being most effective. Thus, spontaneous climbing behaviour of mice can be precisely quantified, dopamine-containing forebrain areas are involved with its expression and it can be potently modified by dopamine agonists and antagonists.