An assessment of sympathetic function in isolated tissues from mice given nerve‐growth‐factor antiserum and 6‐hydroxydopamine

Abstract

Summary1. Experiments were done on isolated tissues from mice injected with 09% w/v NaCl solution (saline), 6-hydroxydopamine (6-OHDA), nerve-growthfactor antiserum (NGF-As) or a combination of these agents (NGF-As+ 6-OHDA).2. Fluorescence histochemistry of vasa deferentia showed clear differences between each of the treatments but no such distinction was possible in cardiac ventricle or intestine. 3. Compared with controls, the chronotropic responses of atria to field stimulation were reduced by all three treatments in the order NGF-As< 6-OHDA<NGF-As+6-OHDA. Supersensitivity to noradrenaline occurred in atria from all treated groups. 4. In contrast, vasa deferentia from NGF-As-treated mice responded almost identically with controls to both field stimulation and to exogenous noradrenaline. Considerable functional impairment and noradrenaline supersensitivity were obvious in both the 6-OHDA and the NGF-As + 6-OHDA groups but no distinction could be made between them. 5. The relaxation of superfused ileum following nerve stimulation was reduced in the NGF-As group, whilst preparations from the two groups given 6-OHDA usually gave a motor response which was blocked by atropine. 6. None of the treatments employed in these experiments caused complete sympathectomy although 6-OHDA alone or in combination with NGF-As produced a more pronounced effect than NGF-As alone and the relative ineffectiveness of the latter is discussed. The implications of the motor response after 6-OHDA in ileum when the nerves were stimulated is considered in the light of the cholinergic link hypothesis.

Guanethidine Induced Sympathectomy in the Adult Rat. II. Functional Effects Following Chronic Administration

“…Calculated from results by JOHNSON et al (1975) a potency ratio of 11 for MAP was obtained in pithed rats previoudy sympathectomized by administration of guanethidine to newborn rats, and calculated from results by SIMPSON (1974) a potency ratio of 4 was obtained in anaesthetized and pithed rats sympathectomized by 6-hydroxydopamine and pretreated with propranolol. In isolated atria of mice previously sympathectomized by administering nerve growth factor antiserum, 6-hydroxydopamine or a combination of these agents a 10-20 fold increase in sensitivity to NA was reported (HUGHES et al 1973). The change in slope of the NA doseresponse curve for MAP ( fig.…”

“…was observed by DE CHAMPLAIN & VAN AMERINGEN (1973). In mice immunosympathectomy, sympathectomy by 6-hydroxydopamine, and the combination of nerve growth factor antiserum and 6-hydroxydopamine caused a minor, but insignificant fall in rates of spontaneously beating isolated atria (HUGHES et al 1973). Unchanged heart rate was observed in immunosympathectomized rats (ZAIMIS 1972).…”