Immunoblockade by a specific tachykinin antiserum of the non-cholinergic contractile responses in the guinea-pig isolated bronchus.
1. In the guinea-pig isolated bronchus, capsaicin produced a concentration-dependent contraction which was tetrodotoxin- (1 microM) resistant but abolished by previous exposure to capsaicin. 2. Previous incubation with E7 antiserum (which crossreacts with neurokinin A but not with substance P), but not with control rabbit serum, strongly inhibited the contractile response to capsaicin. 3. The E7 antiserum shifted to the right the concentration-response curve to exogenous neurokinin A but not that to substance P. 4. The E7 antiserum also inhibited the non-cholinergic, slowly developing contraction produced by electrical field stimulation (1-5 Hz). 5. These findings provide additional evidence that tachykinin-like peptides play a major role in the bronchoconstrictor response produced by transmitter secretion from peripheral endings of capsaicin-sensitive afferents in guinea-pig bronchi evoked either by capsaicin or by electrical field stimulation.
Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy.
C A
CA
Maggi
R
R
Patacchini
P
P
Baroldi
E
E
Theodorsson
A
A
Meli
D000403:Airway Resistance / Q000502:physiology; D000818:Animals; D001980:Bronchi / Q000502:physiology*; D002211:Capsaicin / Q000494:pharmacology; D004558:Electric Stimulation; D004600:Eledoisin / Q000276:immunology / Q000502:physiology*; D006168:Guinea Pigs; D007106:Immune Sera / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D015288:Neurokinin A / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology
D007106:Immune Sera; D013373:Substance P; D004600:Eledoisin; D015288:Neurokinin A; D002211:Capsaicin