Somatostatin-like immunoreactivity in a subpopulation of nerve terminals in frog sympathetic ganglia.
A somatostatin-like substance was observed specifically in a subset of B-type nerve terminals in frog paravertebral ganglia. The middle ganglia (4th and 5th) of the sympathetic chain contained the highest proportions of somatostatin-positive terminals, with decreasing proportions in more caudal or rostral ganglia. Intracellular recordings from the 6th ganglion demonstrated that it contained both B and C neurons. Although prolonged depolarizing potentials were observed in B and C neurons after bursts of stimuli in C-type preganglionic axons, no slow potentials were observed after stimulating somatostatin-positive B-type axons. In addition, no effects of exogenously applied somatostatin were observed on the membrane potentials of B neurons. The present results are compared to a growing list of autonomic systems where peptidergic transmitters appear to have only subtle or no acute electrical consequences on postsynaptic neurons.
D000818:Animals; D004594:Electrophysiology; D005260:Female; D005728:Ganglia, Sympathetic / Q000276:immunology* / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D009411:Nerve Endings / Q000276:immunology*; D011892:Rana catesbeiana / Q000276:immunology*; D013004:Somatostatin / Q000276:immunology*
D013004:Somatostatin