Objective To investigate the expression of histamine in the cardiac sympathetic fibers from the guinea pig superior cervical ganglion and its coexistence with norepinephrine so as to provide morphological evidence for histamine as a cardiac sympathetic neurotransmitter.Methods Biotinylated dextranamine(BDA) anterograde tracing and immunofluorescence histochemical staining for histamine/norepinephrine were applied.Results After injection of BDA into the superior cervical ganglion,BDA labeled sympathetic fibers in the left and right atria and ventricle were observed.Meanwhile,the tracing fibers proved histamine-like immunoreactive or both histamine and norepinephrine-like immunoreactive.Conclusion Histamine is expressed in the cardiac sympathetic fibers from the guinea pig superior cervical ganglion and coexisted with norepinephrine.

Non-small cell lung cancer(NSCLC)is a prevalent and aggressive global malignancy.Conventional sur-gical treatments,radiotherapy,chemotherapy,and targeted therapies often fall short in halting disease progression due to inher-ent limitations,resulting in suboptimal prognosis.Despite the advent of immunotherapy drugs offering new hope for NSCLC treatment,current efficacy remains insufficient to meet all patient needs.Therefore,actively exploring novel immunotherapeu-tic approaches to further reduce mortality rates in NSCLC patients has become a crucial focus of NSCLC research.This article aims to systematically review the anti-tumor effects ofinterleukin-21 and follicular helper T cells in NSCLC immunotherapy by summarizing and analyzing relevant literatures from both domestic and international sources,as well as exploring the potential for enhancing NSCLC treatment prospects through immune checkpoint regulation via immunotherapeutic means.