title: Control of glycogenolysis and hemodynamics in perfused rat liver by the sympathetic innervation. Dependence on stimulation frequency and duration.
abstract: Perivascular stimulation of the hepatic nerves in the in situ perfused rat liver with a constant frequency of 20 Hz over a constant period of 5 min had previously been shown to cause an increase of glucose output, a shift from lactate uptake to release, a reduction in perfusion flow (Hartmann et al. (1982) Eur. J. Biochem. 123, 521-526) and an overflow of noradrenaline into the hepatic vein (Beckh et al. (1982) FEBS Lett. 149, 261-265). In the present study the dependence of the metabolic and hemodynamic effects on the frequency between 1 and 30 Hz and duration of stimulation between 0.5 and 5 min was investigated. Over a constant stimulation period of 5 min the alteration in glucose exchange was maximal with a frequency of 10 Hz and half-maximal with 4 Hz. The corresponding values for the exchange of lactate were 5 Hz and 2 Hz, respectively, and for the perfusion flow 2.5 Hz and 1.5 Hz, respectively. An increase of noradrenaline overflow was not observed with the lower frequencies of 1 and 2.5 Hz; it was maximal at 10 Hz and half-maximal at 6.5 Hz. At a constant frequency of 20 Hz the increase in glucose release was maximal with a total stimulation period of 1 min and half-maximal with a period of 0.4 min. An essentially maximal alteration of lactate exchange and perfusion flow as well as of noradrenaline overflow was also effected by a stimulation period of 1 min.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism*; D006439:Hemodynamics; D007773:Lactates / Q000378:metabolism; D008099:Liver / Q000098:blood supply / Q000294:innervation* / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D012039:Regional Blood Flow; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D007773:Lactates; D006003:Glycogen; D005947:Glucose; D009638:Norepinephrine