Table 1.

Fitting of data from Figure 7 with the different models discussed here

Model	Parameter	Phenylephrine	Oxymetazoline	Naphazoline	Clonidine	Tolazoline
(A) Experimental data from Ruffolo et al. (1979)
	E max	1.00	0.73	0.48	0.33	0.10
	log ED50	−7.55	−6.77	−8.20	−7.60	−6.64
	log K d 1	−6.46	−6.36	−8.23	−7.66	−6.69
(B) Standard E max (Prism: log[agonist] vs. response ‐ variable slope [four parameters], eq. 9; Hill slope = 1, Bottom = 0)
	Top	99.6 ± 1.26	72.9 ± 1.04	48.0 ± 0.56	33.2 ± 0.70	10.0 ± 1.08
	LogEC50	−7.55 ± 0.035	−6.77 ± 0.029	−8.20 ± 0.027	−7.60 ± 0.047	−6.64 ± 0.174
	r 2	0.9958	0.9978	0.9972	0.9937	0.9491
	SSE	56.25	10.50	4.26	7.52	2.95
(C) Present (Prism implementation of present model, eq. 31 with no amplification γ = 1 [i.e., eq. 26] [n = 1])
	ε	0.996 ± 0.0126	0.729 ± 0.0104	0.480 ± 0.0056	0.332 ± 0.0070	0.100 ± 0.0108
	γ	1	1	1	1	1
	log K d	−7.55 ± 0.035	−6.77 ± 0.029	−8.20 ± 0.027	−7.60 ± 0.047	−6.64 ± 0.174
	r 2	0.9958	0.9978	0.9972	0.9937	0.9491
	SSE	56.25	10.50	4.26	7.52	2.95
(D) Operational model [Prism implementation for partial agonist, eq. 19; n (Hill) = 1, Basal = 0]
	Effectmax	99.58 ± 0.826	99.58 ± 0.826	99.58 ± 0.826	99.58 ± 0.826	99.58 ± 0.826
	logK A	(n.u.)b/~ −1.527 ± 6082	−6.20 ± 0.051	−7.91 ± 0.056	−7.42 ± 0.078	−6.59 ± 0.312
	τ	(n.u.)b/~106.0 b ± too wide	2.731 ± 0.196	0.931 ± 0.042	0.499 ± 0.025	0.112 ± 0.024
	LogEC50	−7.55 ± 0.023/(n.u.)	(not used)	(not used)	(not used)	(not used)
	r 2	0.9958	0.9978	0.9972	0.9937	0.9491
	SSE	56.25	10.50	4.26	7.52	2.95
(E) Present (Prism implementation of present model, eq. 31; K d from experimental [n = 1])
	ε	1	0.1739 ± 0.0274	0.0637 ± 0.0106	0.0369 ± 0.0064	0.0088 ± 0.0022
	γ	11.88 ± 2.02	11.88 ± 2.02	11.88 ± 2.02	11.88 ± 2.02	11.88 ± 2.02
	log K d (from exp.)a	−6.46	−6.36	−8.23	−7.66	−6.69
	↓c
	E max	1.000	0.714	0.447	0.313	0.096
	log EC50(K obs)	−7.53	−6.82	−8.46	−7.81	−6.73
	r 2	0.9957	0.9964	0.9508	0.9736	0.9430
	SSE	57.22	17.21	76.18	31.71	3.30

All fitting were done with models implemented in GraphPad Prism, and in addition to the calculated parameters (shown with their calculated standard errors), descriptors of the quality of fit (correlation coefficient, r ², and sum of squared errors, SSE) are also included.

^aExperimental data, average of log K _A (Table 3) and log K _B (Table 4) from Ruffolo et al. (1979).

^bThe operational model as implemented in GraphPad Prism, does not fit K _A and τ for a full agonist (not used) as well‐defined values cannot be obtained. A set of values were calculated here for illustration by re‐using the data of the full agonist (phenylephrine) as another partial agonist.

^cDerived values for the present model (using eq. 33).