文档介绍：Section III Cell to munication and Signal Transduction across Membrane
冯鉴强教授
Cell to munication
Several types munication
1)Jap junction(缝隙连接)
Two neighboring municate by a connexin(连接蛋白)which is a protein channel allowing the substances exchanges(amino acid, ions, ATP and CAMP etc.) and electrical signals transmission.
For instant, heart muscle
paracine
cells secrete substances(hormones, etc) that diffuse into the extracellular fluid and affected neighboring cells.
autocrine(自分泌)
a cell secretes substances that affect the function of the same cell by binding to the cell surface receptors.
Long munication(长距离通讯)
endocrine
glands or specialized cells release into the circulating blood chemicals(hormones) that influence the function of cells at another location
neuroendocrine
neurons release neurohormones(神经激素)into the circulating blood to influence the function of cells at another location.
neural
electrical impulses(action potential) reach the end of nerve fiber→ releasing neurotrans mitter(chemical signal) into synaptic junctions→ influencing the function of post synaptic neuron.(Fig 2-19)
cytokine(细胞因子)
It is an important factor in the chemical signal transduction.
At early studies, mainly focus on the proteins which participate in the immunological reactions.
For instant, interleukin(白介素)and interferon(干扰素) etc.
Recently, extend to many regulatory peptides including NGF, BDNGF etc.
Regulatory manners:
autocrine and paracrine: in the cell development and differentiation( local signal)
long munication: in the stress reaction or the inflammatory reaction.
Receptors and Signal Transduction across Membrane
Receptors
The first step of a hormone’s action is to bind to specific receptors at the target cell.
After the bines with its receptor, usually initiates a cascade(级联式) of reactions in the cell.
The locations for different types of hormone receptors
In or on the surface of the cell membrane (membrane receptors): for the protein, peptide and catechol