In vitro denervation of the rat vas deferens through hypothermic storage.
1. The rat vas deferens was excised, stored at 4-6 degrees C and tested after 24, 48, 72 or 96 h for its contractile activity and for the presence of innervation. 2. The maximal contractile capacity of the vas, tested through cumulative concentrations of barium chloride (3 x 10(-2) M) was progressively reduced from about 110 mm to about 63 mm after 72 h, without further decay after 96 h. Spontaneous rhythmic contractions were practically absent. 3. A loss of endogenous pools of catecholamines was indicated by four parameters: (a) a decline of about 80% after 24 h and of more than 95% after 48 h of the contractile effect of the indirect sympathomimetic agonist tyramine; (b) a fall of about 20%, 50% and 85% on the concentration of noradrenaline, respectively after 24, 48 and 72 h; (c) a fall of about 25% and 90% after respectively 24 and 48 h, of the activity of dopamine-beta-hydroxylase (DBH); (d) a decline of noradrenaline-induced histofluorescence on cross sections of the vas. 4. A loss of neuronal uptake capacity was indicated by: (a) a progressive variation of the apparent affinity for adrenaline, expressed as pD2 values, that increased by about 1.5 log units (corresponding to a 30 fold potentiation) after 72 h, and (b) a reduction of the ability of cocaine to potentiate the contractile effects of adrenaline. 5. The pD2 values for barium chloride, 5-hydroxytryptamine (5-HT) and histamine were not significantly changed, while the corresponding value for acetylcholine was slightly but significantly reduced by about 0.8 log units. 6. The maximal heights of concentration-response curves for noradrenaline, acetylcholine, histamine and 5-HT were reduced by 42-66% in relation to controls. However, when this reduction was measured in relation to the corresponding barium effect, by means of the relative responsiveness ratio (p), a small though significant increase was observed for noradrenaline, and a fall for the other drugs.7. It is concluded that: (1) the values for the various biochemical and pharmacological parameters decline at different rates, though revealing altogether that denervation is completed by at least 85% after 72 h of hypothermic storage; (2) two of the results, i.e., the lack of spontaneous rhythmic contractions and the lack of increased contractile effects for acetylcholine, 5-HT and histamine, indicate that in these conditions the vas is devoid of the so-called nonspecific signs of denervation.
Jurkiewicz
N H
NH
Department of Pharmacology, Escola Paulista de Medicina, São Paulo, Brazil.
Garcia
A G
AG
Jurkiewicz
A
A
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D017609:Barium Compounds; D002395:Catecholamines / Q000378:metabolism; D002712:Chlorides; D003080:Cold Temperature; D003714:Denervation; D004837:Epinephrine / Q000378:metabolism / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology; D014649:Vas Deferens / Q000294:innervation* / Q000378:metabolism / Q000502:physiology
D017609:Barium Compounds; D002395:Catecholamines; D002712:Chlorides; C024986:barium chloride; D001464:Barium; D012701:Serotonin; D006632:Histamine; D000109:Acetylcholine; D009638:Norepinephrine; D014439:Tyramine; D004837:Epinephrine