What is in a rat's saliva? - briefly
Rat saliva is a watery mixture containing enzymes (e.g., amylase, lysozyme), antimicrobial proteins, electrolytes (sodium, potassium, chloride), and trace hormones such as cortisol. It also includes mucins that lubricate oral tissues.
What is in a rat's saliva? - in detail
Rat saliva is a complex biological fluid that supports feeding, grooming, and disease transmission. It contains water, electrolytes, enzymes, proteins, and bioactive molecules, each contributing to specific physiological functions.
The aqueous component makes up about 95 % of the secretion, providing a medium for dissolved substances. Major electrolytes include sodium, potassium, chloride, calcium, and magnesium, maintaining osmotic balance and pH regulation.
Enzymatic activity is dominated by salivary amylase, which initiates carbohydrate digestion, and by lysozyme, a bacteriolytic protein that reduces microbial load on oral surfaces. Additional enzymes such as lipase and proteases are present in lower concentrations, facilitating lipid breakdown and protein turnover.
Proteinaceous factors comprise several families:
- Mucins – high‑molecular‑weight glycoproteins that lubricate oral tissues and trap particles.
- Antimicrobial peptides – defensins and cathelicidins that disrupt bacterial membranes.
- Immunoglobulins – primarily IgA, providing passive immunity against pathogens encountered during foraging.
- Growth factors – epidermal growth factor (EGF) and nerve growth factor (NGF) that promote epithelial repair and neuronal health.
Hormonal constituents include corticosterone and insulin‑like growth factor, reflecting systemic metabolic status and influencing feeding behavior.
Trace elements such as zinc and copper are bound to metalloproteins, contributing to enzymatic stability and antimicrobial efficacy.
Collectively, these components enable efficient food processing, oral hygiene, and serve as vectors for pathogens such as hantavirus and Leptospira, underscoring the fluid’s role in both normal physiology and disease ecology.