Smooth Muscle Layer-Specific Variations in the Autonomic Innervation of Bovine Myometrium

摘要: Abstract 1. To clarify the autonomic innervation regulating longitudinal muscle (LM) and circular (CM) motility in bovine uterus, functional (nerve stimulation, adrenergic drug responsiveness) biochemical studies (catecholamine content, radioligand binding) were conducted on parous luteal-phase myometrium. 2. Electrical field stimulation (EFS; 60 V, 0.5-msec duration) caused tetrodotoxin (1 μM)-sensitive contractions a frequency-dependent manner (0.5–20 Hz) both LM CM layers. 3. The EFS-induced potentiated by propranolol conspicuously decreased phentolamine, yohimbine, idazoxan or guanethidine, but unaffected prazosin atropine. 4. On other hand, only slightly idazoxan, yohimbine insensitive to propranolol, 5. noradrenaline content was about five times higher than that CM. 6. Noradrenaline, adrenaline, clonidine, xylazine, UK14,304 phenylephrine concentration-dependent of smooth 7. Clonidine, xylazine more potent contractile agents phenylephrine. 8. response competitively antagonized not prazosin. 9. Binding using [ 3 H]-prazosin H]-rauwolscine revealed myometrium contained α 1 - 2 -adrenoceptors, -type receptor dominant (94% α-adrenoceptors) (88%) 10. distribution α-adrenoceptors layer-specific; is, concentration -receptors same as CM, 2.6 11. results present study indicate there are layer-specific variations (exclusive [minor] plus nonadrenergic, noncholinergic [major] CM), which responsive excitatory endogenous exogenous noradrenaline, layers