Peptide is a kind of bioactive peptide and an indispensable participant in life activities. It involves hormones, nerves, cell growth and reproduction and other fields. Its main role is to regulate the functional activities of various systems, organs and cells in the body. Peptides and proteins are only the difference between the length of peptide chains, and there is no strict difference. Generally, those with less than 100 amino acids are called peptides(click to see custom peptide synthesis price list), while those with more than 100 amino acids are called proteins

1. Vasopressin

The discovery of vasopressin can be traced back to 1895. Ohver and Schafer found that there was a powerful vasopressin in the extract of the posterior pituitary gland, which was composed of 9 amino acids. In 1953, DuVigneaud et al. separated and purified neurohypophysin from it, determined the chemical structures of vasopressin (AVP or antidiuretic hormone, ADH) and oxytocin (OXT), and conducted artificial synthesis. This is the first peptide hormone isolated and identified from neural tissue. In 1977, Brownstein et al found the precursor molecules of AVP and OXT in the supraoptic nucleus of rats. In 1982, Land et al cloned AVP and OXT precursor cDNA from the hypothalamus of cattle. The main synthesis sites of AVP and OXT are the paraventricular nucleus (PVN) and supraoptic nucleus (SON). In addition, AVP and OXT are also synthesized in the suprachiasmatic nucleus, stria terminalis nucleus, amygdala, dorsal median nucleus and locus coeruleus.

After entering the blood circulation, AVP is distributed in almost all extracellular fluids. It is a substance with relatively low molecular weight and easy to penetrate the peripheral tissues and glomerular capillaries. The total clearance time of human AVP is 30-40 min, including metabolic degradation and renal excretion, indicating that the action time of human endogenous AVP is only about 30 min. AVP has two kinds of receptors, v receptor is mainly distributed in vascular smooth muscle and V2 receptor is mainly distributed in renal tubule. AVP makes vascular smooth muscle contract and blood pressure rise. When AVP in blood increases, on the one hand, it can reduce cardiac output, on the other hand, it can increase total peripheral resistance. In the state of hypotension and hypovolemia, AVP is released and acts on V receptors on smooth muscle cells, leading to vasoconstrictive effect, especially after acute hemorrhage, which is very significant and beneficial to the recovery of blood pressure. AVP can also act on V2 receptor of vascular smooth muscle, causing certain vascular bed relaxation.

Naitoh observed the effects of blocking v and v2 receptors alone or in combination with captopril on rat models of congestive heart failure. Combined blocking reduced blood pressure and the mass of left and right ventricles. Stallone pointed out that [. There is gender difference in the vasoconstriction caused by AVP. The degree of vasoconstriction caused by AVP in female rats is 3 times higher than that in male rats. This may involve special regulation of AVP signal transduction pathway. With the change of age, the structure and function of cardiovascular system have obvious changes. The left ventricle is slightly hypertrophied, the resting heart rate is slowed down, and the ventricular filling rate decreases at an early stage (exenatide impurities). On the contrary, the end diastolic diameter and end systolic diameter, stroke output and ejection fraction base This has not changed. Age affected the regulation of cardiovascular system, increased sympathetic activity, and increased circulating AVP and ANP When DOCA (deoxycorti costerone acetate) salt hypertensive rats were injected with AVP, the decrease of cardiac output was related to the dose