Figure 3.
cGMP dynamics in OSNs upon physiological stimuli (odors). Conditions as in Figure 2. A–D, Examples of the cGMP kinetics in OSNs treated with different concentrations of odors, bath applied: odors, 1 μm, n = 3, t1/2 cilia-dendrite = 3 ± 0.3 min, soma = 4.2 ± 0.3 min, axon terminus-growth cone = 2.9 ± 0.2 min; t test t1/2 cilia-dendrite-soma *p = 0.04, axon terminus growth cone-soma *p = 0.02, cilia dendrite-axon terminus growth cone p = 0.8 (A); odors, 50 μm, n = 6, t1/2, cilia-dendrite = 2.7 ± 0.5 min, soma = 3.1 ± 0.5 min, axon terminus-growth cone = 2.4 ± 0.5 min, t test t1/2 cilia dendrite-soma *p = 0.03, axon terminus growth cone-soma *p = 0.02, cilia dendrite-axon terminus growth cone p = 0.4 (B); odors, 200 μm, n = 20, t1/2 cilia-dendrite = 2.2 ± 0.3 min; soma = 2.4 ± 0.4 min; axon terminus-growth cone = 2 ± 0.3 min; t test t1/2 cilia dendrite-soma *p = 0.03; axon terminus growth cone-soma *p = 0.02, cilia dendrite-axon terminus growth cone p = 0.3 (C); and odors, 200 μm, bath applied for 5–7 min and then washed away (D); and cGMP rise in response to odors (1 mm in the pipette) locally applied with a glass pipette directed to the axon terminus (E). F, G, Examples of cGMP dynamics (FRET, 480/545 nm) (F) and calcium dynamics (fura-2, 380 nm component) (G) in the same neuron, transfected with the sensor for cGMP and loaded with fura-2, treated with odors (200 μm, bath applied). H, Example of cGMP dynamics in an OSN not responsive to odors (200 μm, bath applied), but responsive to KCl (50 mm) subsequently bath applied. I, example of cGMP dynamics in a HEK cell, not expressing OR (used as controls), treated with odors (200 μm, bath applied). Primary cultures of OSNs were used in all experiments. Solid lines represent the cGMP dynamics (A–F, H); dotted lines denote Ca2+ dynamics (G). Blue line, Cilia-dendrite; pink line, soma; green line, axon terminus-growth cone; red line, cGMP kinetics in HEK cell (I).