Linked Functions and Reciprocal Effects

Linked Functions and Reciprocal Effects in Hemoglobin A Second Look Jeffries Wyman, Jr. 

J. Wyman, Linked functions and reciprocal effects in hemoglobin A second look, Adv. Protein Chem. 19, 223-286 (1964).. 

In thermodynamics, this is referred to as a Maxwell equation. This equation is derived later in Section 4.8. Thus the effect of pMg on the binding of hydrogen ions is the same as the effect of pH on the binding of magnesium ions in short, these are reciprocal effects. The bindings of these two ions are referred to as linked functions. Equation 1.3-17 can be confirmed by plotting these two derivatives, and the same plot is obtained in both cases. This would be a lot of work to do by hand, but since Mathematical can take partial derivatives, this can be done readily with a computer. The two plots are identical and are given in Fig. 1.8. 

In fact, the SSRI-RBD link sounds a lot like the Thorazine-tardive dyskinesia tie-in, doesn t it What possibly common underlying mechanism could unite these apparently disparate phenomena One answer is dopamine, whose production by the substantia nigra is deficient in spontaneous Parkinsonism. Dopamine is blocked, hence rendered functionally deficient, by the antipsychotics that produce both immediate and delayed Parkinsonian side effects. Serotonin inhibits dopamine, which means that potentiating serotonin with SSRIs could also render dopamine less functionally efficacious. Acetylcholine is in dynamic reciprocity with both serotonin and dopamine. Acetycholine causes an increase in dopamine s efficacy in some circuits and a decrease in others. 

---