Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carbachol (0.1-300 mumol/L) potentiated contractions to field stimulation (0.1 Hz, 1 ms, supramaximal V) in the rat epididymal and prostatic vas deferens. Desensitization of P2-purinoceptors by exposure to alpha,beta-methylene ATP (30 mumol/L) markedly reduced (greater than 80%) the potentiating effect of carbachol in the prostatic vas deferens but only moderately reduced (about 20%) the maximal stimulated response to carbachol in the epididymal segment. The presence of prazosin (10 mumol/L) and yohimbine (10 mumol/L), being selective alpha 1- and alpha 2-adrenoceptor antagonists, did not modify the attenuation of carbachol potentiation caused by alpha,beta-methylene ATP treatment. At 0.1 mmol/L, alpha,beta-methylene ATP had no significant effect on the binding of [3H]QNB to muscarinic cholinergic receptors. It is concluded that carbachol may potentiate the contractions to field stimulation in the prostatic vas deferens via an enhancement of purinergic neurotransmission. The molecular mechanism of carbachol potentiation in the epididymal vas deferens remains to be established.
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PMID:Effects of alpha,beta-methylene ATP on potentiation of contractions to field stimulation of rat vas deferens by carbachol. 281 95

The aim of the present study was to characterize the muscarinic acetylcholine receptor subtypes present in the caput and cauda of rat epididymis. The specific binding of [3H]quinuclidinyl benzilate ([3H]QNB) to epididymal membranes was time dependent, temperature dependent, and saturable. The cauda epididymis showed higher affinity to [3H]QNB and higher muscarinic receptor density when compared to the caput region. The [3H]QNB binding was tested in competition studies with different muscarinic receptor antagonists. Each antagonist tested displaced [3H]QNB bound to caput and cauda epididymal membrane with similar affinity. Correlation among the negative logarithm of inhibition constant values (pK(i)) for these antagonists obtained in the epididymis with their correspondent published pK(i) values obtained in tissues that expressed each receptor subtype (M1, M2, M3, and M4) indicated that the muscarinic receptors present in caput and cauda epididymis belong to the muscarinic M2 receptor subtype. When reverse transcription-polymerase chain reaction was used to identify muscarinic receptor mRNA subtypes in the epididymis, only m2 transcripts were detected in the caput region, while both m2 and m3 mRNA subtypes were observed in the cauda region. In conclusion, these results demonstrate that muscarinic receptors are present in the rat epididymis, with expression levels dependent on the region of the epididymis analyzed. Thus, the cholinergic neurotransmitter in the epididymis may be a factor controlling contractility and/or the luminal fluid microenvironment.
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PMID:Characterization of muscarinic acetylcholine receptors in the rat epididymis. 1156 33

The effect of testosterone on the expression of muscarinic acetylcholine receptor (mAChR) subtypes was studied in the rat epididymis, at mRNA and protein level. The rat androgen status was monitored by measuring plasma testosterone level and caput and cauda epididymis wet weight. Ribonuclease protection assay (RPA) and [3H]quinuclidinyl benzilate ([3H]QNB) binding assay were performed in the caput and cauda epididymis from control (50-day old), castrated, castrated and treated with testosterone and sexually immature (30-day old) rats. The expression of each mAChR transcript subtype differed depending on the epididymal region analyzed and rat testosterone and/or testicular factors status. In control rats, RPA showed the presence of mRNA for M1, M2 and M3 mAChR in the caput and cauda epididymis. The abundance of m2 and m3 transcripts in the cauda was higher than that in the caput epididymis. Low amount of m1 transcript was observed in both regions. Orchidectomy increased m1 mRNA amount in the caput and cauda epididymis when compared to control rats, an effect slightly modified by testosterone replacement. Although orchidectomy down-regulated the level of m2 transcript in both epididymal regions, castration significantly increased m3 mRNA amount in the caput region. These effects on m2 and m3 transcripts were prevented by testosterone replacement to castrated rats. Similar abundance of m3 transcript, however, was detected in the cauda epididymis of all experimental group tested. [3H]QNB binding studies revealed that orchidectomy down-regulated the number of mAChR detected in both epididymal regions, an effect also prevented by testosterone replacement. Thus, testosterone and/or testicular factors may play a role in the regulation of mAChR expression in the rat epididymis.
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PMID:Effects of testosterone on muscarinic acetylcholine receptors in the rat epididymis. 1592 97