Neural modulation of bovine mesenteric lymph node contraction.
Spontaneous isometric contractions and field-evoked responses were recorded in vitro from strips of bovine mesenteric lymph node capsule. Field stimulation (0.3 ms pulses, 60 V nominal, 2 min trains) at frequencies > or = 2 Hz evoked a frequency-dependent increase in baseline tension which was maximum at frequencies > or = 16 Hz. Evoked contractions were significantly reduced (P = 0.02) by the neurotoxin tetrodotoxin (10(-6) M) although they were unaffected by the alpha-adrenoceptor antagonists phentolamine, rauwolscine and prazosin (3 x 10(-6) M). Similarly, responses were unaffected by the beta-adrenoceptor antagonist propranolol (10(-6) M), the cholinergic antagonist atropine (10(-6) M) or the uptake blocker cocaine (10(-6) M). Field-evoked contraction was also unaffected by a 30 min exposure to alpha,beta-methylene ATP (10(-6) M). The results suggest that bovine lymph node capsular smooth muscle is innervated by excitatory nerves which are non-adrenergic, non-cholinergic and non-purinergic in nature.
Hughes
G A
GA
Biomedical Sciences Research Centre, University of Ulster, Coleraine.
Allen
J M
JM
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002417:Cattle; D003042:Cocaine / Q000494:pharmacology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D007537:Isometric Contraction / Q000502:physiology; D008198:Lymph Nodes / Q000294:innervation / Q000502:physiology*; D008643:Mesentery; D009474:Neurons / Q000502:physiology*; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D015016:Yohimbine; D013779:Tetrodotoxin; D001285:Atropine; D000255:Adenosine Triphosphate; D011433:Propranolol; D003042:Cocaine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D011224:Prazosin; D010646:Phentolamine