Purinergic signalling - PubMed (original) (raw)
(a) and (b) Sucrose gap records from smooth muscle of guinea-pig taenia coli showing inhibitory junction potentials in response to stimulation of intrinsic nerves. Frequencies of stimulation for (a) 1/s and (b) 30/s. Upper trace tension, and lower trace membrane potential. Note the phase of excitation in (b) which follows cessation of stimulation (From Burnstock et al. (1963). Reproduced with kind permission from Nature Publishing Group). (c) Sucrose gap recording of membrane potential changes in smooth muscle of guinea-pig taenia coli in the presence of atropine (0.3 μ
M
) and guanethidine (4 μ
M
). Transmural field stimulation (0.5 ms, 0.033 Hz, 8 V) evoked transient hyperpolarisations or inhibitory junction potentials, which were followed by rebound depolarisations. Tetrodotoxin (TTX, 3 μ
M
) added to the superfusing Krebs solution (applied at arrow) rapidly abolished the response to transmural field stimulation. (From Burnstock (1986). Acta Physiol. Scand. 126, 67–91. Reproduced with kind permission from Blackwell Publishing). (d) Effects of bretylium (BRET, 5 × 10−6 g ml−1) on responses to stimulation of the guinea-pig perivascular nerve–taenia coli preparation after atropine. Bretylium abolishes responses to stimulation of the perivascular nerves at 30 pulses/s (P, at dots), but only reduced responses to field stimulation of the taenia with 10 pulses/s (T, at triangles) (From Burnstock et al. (1966). Reproduced with kind permission from Blackwell Publishing). (e) Responses of the guinea-pig taenia coli to intramural nerve stimulation (NS, 1 Hz, 0.5 ms pulse duration, for 10 s at supramaximal voltage) and ATP (2 × 10−6
M
). The responses consist of a relaxation followed by a ‘rebound contraction'. Atropine (1.5 × 10−7
M
), guanethidine (5 × 10−6
M
) and sodium nitrite (7.2 × 10−4
M
) were present. (From Burnstock & Wong, 1978, Br. J. Pharmacol. 62, 293–302. Reproduced with kind permission from the Nature Publishing Group). (f) A comparison of the contractile responses of the guinea pig bladder strip to intramural nerve stimulation (NS: 5 Hz, 0.2 ms pulse duration and supramaximal voltage) and exogenous ATP (8.5 μ
M
). Atropine (1.4 μ
M
) and guanethidine (3.4 μ
M
) were present throughout (From Burnstock et al., 1978. Reproduced with kind permission from the Nature Publishing Group).