Liu M T, Kirchgessner A L
Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
Am J Physiol. 1997 Dec;273(6):G1273-89. doi: 10.1152/ajpgi.1997.273.6.G1273.
The morphology, neurochemistry, and electrical properties of guinea pig pancreatic neurons were determined. The majority of neurons expressed choline acetyltransferase (ChAT) immunoreactivity; however, ChAT-negative neurons were also found. Both cholinergic and noncholinergic neurons expressed nitric oxide synthase (NOS) immunoreactivity. Three types of pancreatic neurons were distinguished. Phasic neurons fired action potentials (APs) at the onset of depolarizing current pulse, tonic neurons spiked throughout the duration of a suprathreshold depolarizing pulse, and APs could not be generated in nonspiking neurons, even though they did receive synaptic input. APs were tetrodotoxin sensitive, and all types of neurons received fast and slow excitatory postsynaptic potentials (EPSPs). Fast EPSPs had cholinergic and noncholinergic components. The majority of pancreatic neurons appeared to innervate the acini. NOS- and/or neuropeptide Y-immunoreactive phasic and tonic neurons were found. Microejection of 5-hydroxytryptamine (5-HT) caused a slow depolarization that was inhibited by the 5-HT1P antagonist N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide and mimicked by the 5-HT1P agonist 6-hydroxyindalpine. A pancreatic 5-HT transporter was located, and inhibition of 5-HT uptake by fluoxetine blocked slow EPSPs in 5-HT-responsive neurons by receptor desensitization.
对豚鼠胰腺神经元的形态、神经化学和电特性进行了测定。大多数神经元表达胆碱乙酰转移酶（ChAT）免疫反应性；然而，也发现了ChAT阴性神经元。胆碱能和非胆碱能神经元均表达一氧化氮合酶（NOS）免疫反应性。区分出三种类型的胰腺神经元。相位性神经元在去极化电流脉冲开始时发放动作电位（APs），紧张性神经元在阈上性去极化脉冲持续期间持续发放动作电位，而非发放性神经元即使接受了突触输入也不能产生APs。APs对河豚毒素敏感，所有类型的神经元均接受快速和慢速兴奋性突触后电位（EPSPs）。快速EPSPs具有胆碱能和非胆碱能成分。大多数胰腺神经元似乎支配腺泡。发现了NOS和/或神经肽Y免疫反应性的相位性和紧张性神经元。微量注射5-羟色胺（5-HT）引起缓慢去极化，该去极化被5-HT1P拮抗剂N-乙酰-5-羟色胺基-5-羟色胺酰胺抑制，并被5-HT1P激动剂6-羟基吲达品模拟。定位了胰腺5-HT转运体，氟西汀对5-HT摄取的抑制通过受体脱敏作用阻断了5-HT反应性神经元中的缓慢EPSPs。
