The distribution of serotonin(5-HT), phenylethanolamine-N-methyltransferase (PNMT), substance P(SP) and leu-enkephalin(L-ENK) immunoreactive neurons in the rostral ventrolateral medulla (RVL) of the cat was studied with the immunohistochemical ABC technique, and the projection of 5-HT, SP and L-ENK positive neurons of the RVL into the thoracic cord was preliminarily investigated by a combined fluorescent retrograde transport and immunofluorescence method. The results indicate that 5-HT, PNMT, SP and L-ENK immunoreactive neurons mentioned above were localized primarily in the caudal part of nucleus paragigantocellularis lateralis and the rostral part of nucleus lateralis reticularis. SP positive cell bodies in the reticular formation close ventrolateral to nucleus ambiguus were also found. Some 5-HT, SP and L-ENK positive cells were situated in the area near the pia mater. In the most area of the RVL, 5-HT, PNMT, SP and L-ENK immunoreactive cell bodies had an overlapping distribution. 5-HT or PNMT or L-ENK positive neurons crowded, intertwined each other with their processes in the region at the levels 1.0-3.5mm caudal to trapezoid body, about 3.3mm lateral to the midline and about 0.8mm from the ventral surface of the medulla, and formed a longer or shorter continuous cell column which ran in the rostrocaudal direction. These three columns nearly coincided with each other at the level 1.5-2.5mm caudal to trapezoid body. Part of 5-HT, SP and L-ENK positive neurons in the RVL projected into the thoracic cord. The functional significance of these substances in the RVL was also discussed.

Quantitative proteomics is a mass spectrometry-based toolkit used to analyze and quantify entire proteins contained in whole cells, tissues or organisms. It has become an increasingly important element in exploring the mechanism of various biological processes such as discovering novel biomarkers and unknown drug targets. Emerging advances in biological mass spectrometry instrumentation and data acquisition methodologies have provided a state-of-the-art platform for protein quantification, prompting the research of proteomics evolving from the simple qualitative to the accurate quantitative approach. This review aims to introduce the most recent advancements in mass spectrometry instrumentation and methodologies of data acquisition, focusing on their characteristics and applying fields. It also highlights several significant applications of biological mass spectrometry in pharmaceutical research such as quantifitation of drug transporters and metabolizing enzymes, and pharmacokinetic study of therapeutic peptides and proteins.