Species of differences in postganglionic motor transmission to the retractor penis muscle.
Abstract: 1 Graded motor responses were elicited in isolated, desheathed, thin strips of dog, horse, pig and sheep retractor penis (RP) muscles by field stimulation with trains of 0.2 ms pulses at 10 hertz. These twitches were shown to be neurogenic in all four species, by their prompt extinction in tetrodotoxin.2 alpha-Adrenoceptor blocking drugs abolished the contractile response to noradrenaline and to tyramine in all four species.3 Motor transmission was wholly adrenergic in the horse as in the dog RP because phentolamine rapidly abolished the electrically induced twitches in both these species; but in the pig and in the sheep RP a large proportion of the motor transmission was unaffected by phentolamine given in many times the concentration required to abolish matching noradrenaline-induced contractions.4 Because of the occurrence of periodic spasms in sheep preparations, further investigation of the phentolamine-resistant transmission was confined to the pig RP. Its responses were shown to be entirely postganglionic in origin because they were unaffected by pentolinium.5 In the pig RP a considerable proportion of the phentolamine-resistant motor transmission persisted after combined blockade of alpha- and beta-adrenoceptors by phenoxybenzamine plus propranolol and was more resistant to guanethidine and bretylium than the motor transmission to the dog RP; it was not extinguished after reserpine treatment.6 The pig RP is contracted by histamine but is rather insensitive to acetylcholine, 5-hydroxytryptamine and adenosine-5'-triphosphate. The motor transmission remained unaffected after responses to these substances were blocked by the following antagonists, given alone or in combination: mepyramine, burimamide, atropine, (+)-tubocurarine, methysergide and 2-2'-pyridylisatogen tosylate.
Publication Date: 1978-05-01 PubMed ID: 206306PubMed Central: PMC1668285DOI: 10.1111/j.1476-5381.1978.tb07770.xGoogle Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Comparative Study
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research study examines the varying responses in the retractor penis (RP) muscles of dogs, horses, pigs, and sheep to various pharmacological agents, noting the potential contribution of both neurogenic and adrenergic transmission influences.
Background and Methods
- The scientists initiated motor responses in isolated, desheathed, thin strips of the subject animals’ RP muscles using field stimulation.
- They utilized tetrodotoxin to confirm that these twitch responses were neurogenic, or originating from the nervous system.
- Various adrenoceptor blockers were used to determine the role of adrenergic transmission, which involves the hormone adrenaline.
- The response of each species to different pharmacological agents, including phentolamine, noradrenaline, and tyramine was observed and recorded.
Findings
- In both horses and dogs, the motor transmission was discovered to be entirely adrenergic; this was confirmed by the extinction of electrically induced twitches upon administering phentolamine.
- In contrast, a significant portion of motor transmission in both pigs and sheep was unaffected by phentolamine, suggesting other mechanisms at play.
- This study zeroed in on the pig RP due to spasms seen in sheep preparations. Traces of phentolamine-resistant motor transmission persisted even after combined use of phenoxybenzamine and propranolol, alpha- and beta-adrenoceptor blockers respectively.
- Additional resistance to guanethidine and bretylium, both adrenergic neuron blockers, was noted as well compared to the dog RP.
- Interestingly, despite contracting with exposure to histamine, the pig RP showed little response to acetylcholine, 5-HT, and ATP. Even attempts to block responses to these substances using different antagonists were unsuccessful.
Conclusions
- These results indicate a species-specific difference in postganglionic motor transmission in the RP muscles, with variations in the involvement of adrenergic transmission.
- The study also proposes a non-adrenergic, possibly neurogenic, transmission mechanism in pig RP muscles that requires further investigation.
Cite This Article
APA
Ambache N, Killick SW.
(1978).
Species of differences in postganglionic motor transmission to the retractor penis muscle.
Br J Pharmacol, 63(1), 25-34.
https://doi.org/10.1111/j.1476-5381.1978.tb07770.x Publication
Researcher Affiliations
MeSH Terms
- Animals
- Autonomic Fibers, Postganglionic / physiology
- Dogs
- Guanethidine / pharmacology
- Horses
- Male
- Motor Activity / drug effects
- Neuromuscular Junction / physiology
- Penis / physiology
- Phenoxybenzamine / pharmacology
- Phentolamine / pharmacology
- Sheep
- Species Specificity
- Swine
- Synaptic Transmission / drug effects
References
This article includes 9 references
- Langley JN, Anderson HK. On the Innervation of the Pelvic and Adjoining Viscera: Part I. The Lower Portion of the Intestine.. J Physiol 1895 May 20;18(1-2):67-105.
- Dale HH. On some physiological actions of ergot.. J Physiol 1906 May 31;34(3):163-206.
- Hedqvist P, Von Euler US. Inhibition by alpha- and beta-adrenoceptors of the twitch response to transmural stimulation in the guinea-pig vas deferens.. Eur J Pharmacol 1976 Nov;40(1):153-62.
- Ambache N, Dunk LP, Verney J, Zar MA. Inhibition of post-ganglionic motor transmission in vas deferens by indirectly acting sympathomimetic drugs.. J Physiol 1972 Dec;227(2):433-56.
- Ambache N, Zar MA. Evidence against adrenergic motor transmission in the guinea-pig vas deferens.. J Physiol 1971 Jul;216(2):359-89.
- Luduena FP, Grigas EO. Effect of some biological substances on the dog retractor penis in vitro.. Arch Int Pharmacodyn Ther 1972 Apr;196(2):269-74.
- Luduena FP, Grigas EO. Pharmacological study of autonomic innervation of dog retractor penis.. Am J Physiol 1966 Mar;210(3):435-44.
- von Euler US, Hedqvist P. Evidence for an alpha- and beta2-receptor mediated inhibition of the twitch response in the guinea pig vas deferens by noradrenaline.. Acta Physiol Scand 1975 Apr;93(4):572-3.
- Ambache N, Killick SW, Aboo Aar M. Extraction from ox retractor penis of an inhibitory substance which mimics its atropine-resistant neurogenic relaxation.. Br J Pharmacol 1975 Jul;54(3):409-10.
Citations
This article has been cited 3 times.- Li CG, Rand MJ. Effects of hydroxocobalamin and carboxy-PTIO on nitrergic transmission in porcine anococcygeus and retractor penis muscles.. Br J Pharmacol 1999 May;127(1):172-6.
- Bedwani JR, Blanning PE. Effects of prostaglandin E2 on fast and slow components of the response of the rat vas deferens to field stimulation.. Br J Pharmacol 1983 Jan;78(1):143-50.
- Krell RD, Mccoy JL, Ridley PT. Pharmacological characterization of the excitatory innervation to the guinea-pig urinary bladder in vitro: evidence for both cholinergic and non-adrenergic-non-cholinergic neurotransmission.. Br J Pharmacol 1981 Sep;74(1):15-22.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
