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. 2000 Apr 15;524(Pt 2):549–563. doi: 10.1111/j.1469-7793.2000.t01-2-00549.x

Figure 8. Effects of caffeine, ryanodine and CPA on EJPs and contractions recorded from the sac of the rat penile bulb.

Figure 8

In the presence of nifedipine (10 μM), three impulses delivered at 20 Hz initiated an EJP which consisted of two components and an associated contraction (Aa and b). Caffeine (3 mM) depolarised the membrane and reduced the amplitude of the EJP (Ba). Caffeine (3 mM) caused a transient contraction and also reduced the amplitude of the nerve-evoked contraction (Bb). In a different preparation exposed to nifedipine (10 μM), three impulses delivered at 20 Hz initiated an EJP, which consisted of two components and an associated contraction (Ca and b). Ryanodine (10 μM) depolarised the membrane and reduced the amplitude of the EJP (Da). Ryanodine caused a sustained contraction and also inhibited the nerve-evoked contraction (Db). In another preparation, three impulses initiated an EJP, which consisted of two components and an associated contraction (Ea and b). CPA (10 μM) depolarised the membrane and reduced the amplitude of the EJP (Fa). CPA caused a sustained contraction and also inhibited the nerve-evoked contraction (Fb). A and B,C and D, and E and F were recorded from three different preparations. Resting membrane potentials were -53 mV in A and B, -46 mV in C and D and -50 mV in E and F. Scale bars in F refer to corresponding traces in A–E.