[Electrophysiologic analysis of mediator stores and release in smooth muscle synapses of the nictitating membrane in cats].
At the adrenergic junction of the sympathetic nerve with the medial smooth muscle of the cat nictitating membrane, blocking of the reuptake of noradrenaline with phenoxibenzamine suppressed the amplitude of rhythmic excitatory synaptic potentials. Stimulation of postganglionic sympathetic nerve (10/sec) made the time constant of the first component of the potential 60 sec whereas that of the second component--600 sec. The depression of amplitude seems to be connected with possible decrease in the noradrenaline release and partial exhaustion of its storage. The analysis of the transmitter function showed the release of noradrenaline to a single impulse to be in the reverse relation to the stimulation frequency and at 10/sec to constitute about 3 x 10(-4) (at 20/sec -1.9 X 10(-4)) of the transmitter storage. The replenishment of the transmitter (4 x 10(-6) of the initial operating pool of noradrenaline to a single impulse at 10/sec) was intensified parallel to the increased frequency of adrenergic neurons firing and was able to provide for afferent synaptic transmission within the working frequencies of the afferent part of the sympathetic reflex arch.
D000818:Animals; D001338:Autonomic Fibers, Postganglionic / Q000378:metabolism / Q000502:physiology; D002415:Cats; D004594:Electrophysiology; D007700:Kinetics; D009130:Muscle, Smooth; D009541:Nictitating Membrane / Q000294:innervation*; D009638:Norepinephrine / Q000378:metabolism* / Q000502:physiology; D010643:Phenoxybenzamine / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000378:metabolism* / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission
D010643:Phenoxybenzamine; D009638:Norepinephrine
Elektrofiziologicheskiĭ analiz zapasov i vysvobozhdeniia mediatora v sinapsakh gladkoĭ myshtsy migatel'noĭ pereponki koshki.